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CCD Camera Operating Manual

1. Note You will have to take a new flat field image anytime you change the optical configuration of your telescope such as removing and replacing the optical head in the eyepiece holder 2 Save the flat field image on your disk using the Save command In the following discussions this flat field file will be referred to as FLAT 3 Take your Track and Accumulate image using the Track and Accumulate command and save it on the disk using the Save command In the following discussions this Track and Accumulate image file will be referred to as IMAGE 4 Immediately after saving the IMAGE use the Save Track List command on the PC or activate the Track List window on the Mac and use the Save command to Page 55 Section 5 Advanced Imaging Techniques save the Track and Accumulate track list The track list is a file that describes what alignment operations were done to the individual components of IMAGE to achieve the end result In the following discussions this track list file will be referred to as TRACK 5 Repeat steps 3 and 4 as many times as desired for all the objects you wish to image each time choosing a set of corresponding new names for the IMAGE and TRACK files 6 You will now create a combined flat field image for each Track and Accumulate image you captured Invoke the Add by Track List command The software will bring up a file directory dialog showing all the track list files Select the TRACK file corresponding to the i
2. Page 13 Section 1 Introduction 4 Uncheck all the options except Specify a location as shown below then click the Browse button Add New Hardware Wizard Page 14 Section 1 Introduction 5 Navigate through the Browser window to the My Computer C Program Files SBIG Driver Checker SBIG Drivers directory as shown below Expand each section by clicking on the next to the name For example scroll to the top and click the next to My Computer then click the next to C etc Browse for Folder EM Sbig AL Cedops L Cedops5d 0 CCDSharp EL Driv AQ erreneren nmaa areena aneen ee aaraa nanana nanana nanana ananasa nanasan t a anata a ee E mari on paranna ana iatanahahatatataatetatat Faratatatatatetat Hee ah PRS naranatcnacha cna Click on the SBIG Drivers folder until it is highlighted as shown above then click the OK button This will get you back to the dialog shown above in step 4 but with the location filled out Click the Next button 6 You ll see the dialog below Click the Next button Add Hew Hardware Wizard Page 15 Section 1 Introduction 7 Windows will spin for a while and then present you with the dialog below Click the Finish button and you re done The SBIG cameras actually use two drivers and after you click Finish the system will automatically install the second driver At this point the Fan and LED should come on in the camera Add New
3. 42 45 46 Index 79 temperature regulation 40 49 thermistor 29 TIC 72 TIC 78 46 TIFF format def 70 Track and Accumulate def 70 Track and Accumulate Command 42 55 59 Track and Accumulate mode 45 57 Track Command 59 track list 58 Track List def 70 track mode 45 tracking interface cable TIC 46 72 Tracking Parameters Command 59 Tri Color def 70 tri color images 62 T Thread 62 vane 49 vignetting 30 41 Vignetting def 70 zoom 40
4. These cameras have two CCDs inside one for guiding and a large one for imaging The low noise of the read out electronics virtually guarantees that a usable guide star will be within the field of the guiding CCD for telescopes with F numbers F 6 3 or faster The new cooling design is capable of performance similar to that which used to require an optional second stage cooling booster The relay output plugs directly into most recent commercial telescope drives and is easily modifiable to virtually any drive system As a result you can take hour long guided exposures with ease with no differential deflection of guide scope relative to main telescope and no radial guider setup hassles all from the computer keyboard This capability coupled with the phenomenal sensitivity of the CCD will allow the user to acquire observatory class images of deep sky images with modest apertures The technology also makes image stabilization possible through our AO 7 or self guided spectroscopy with our SGS The new ST X series of cameras incorporate the following design improvements over their parallel based predecessors Uses High Speed USB vs Parallel Port for 10X to 15X faster downloads Adds a new I2C bi directional AUX port for future use LEDs on the Digital Board show Relay Activations helpful for troubleshooting New Heat Exchanger with Water Circulation Capability built in No firmware ROM to update software uploads to camera at boot up New cap
5. image Maximum resolution is determined by the size of the individual CCD pixel The ST 7XE 8XE 9XE 10XE ST 10XME and ST 2000XM can run in High Medium Low and Auto resolution modes Response Factor Response Factor is a multiplier used by CCDOPS to calibrate CCDOPS to a given telescope for photometric calculations The Response Factor multiplied by 6700 is the number of photoelectrons generated in the CCD for a Oth magnitude star per second per square inch of aperture Saturation Saturation refers to the full well capacity of a CCD pixel as well as the maximum counts available in the A D converter The pixel is saturated when the number of electrons accumulated in the pixel reaches its full well capacity The A D is saturated when the input voltage exceeds the maximum The saturation values for the various cameras are shown in the table below Full Well Maximum Electrons Camera Capacity A D Counts per A D P AB ST 5C 50 000 e 65 535 1 25 ST 237 20 000 e 4 095 3 4 ST 237A 20 000 e 65 535 0 7 ST 7XE ST 8XE ABG High Res 50 000 e 20 000 2 3 ST 7XE ST 8XE Med Low Res 100 000 e 65 535 2 3 ST 9XE 180 000 e 65 535 2 8 ST 10XE ST 10XME 77 000 e 65 535 1 5 ST 1001E 180 000e 65 535 2 8 ST 2000XM 45 000e 65 535 0 72 1 4 TC 211 Tracking CCD 150 000 e 65 535 1 3 TC 237 Tracking CCD 20 000 e 65 535 0 72 Sky Background The sky background illumination or brightness is the number of counts in the image in areas free of stars or nebu
6. very dim with a Signal to Noise S N of approximately 3 whereas a perfect camera with no readout noise would give a Signal to Noise of 10 Again this is only important for short exposures or extremely dim objects As the exposure is increased you rapidly get into a region where the signal to noise of the final image is due solely to the exposure interval In the previous example increasing the exposure to 1000 photoelectrons results in a S N of roughly 20 on the camera with 30 electrons readout noise and a S N of 30 on the noiseless camera It is also important to note that with the SBIG CCD cameras the noise due to the sky background will exceed the readout noise in 15 to 60 seconds on the typical amateur telescopes Even the 30 000 priced CCD cameras with 10 electrons of readout noise will not produce a better image after a minute of exposure Full Well Capacity The full well capacity of the CCD is the number of electrons each pixel can hold before it starts to loose charge or bleed into adjacent pixels Larger pixels hold more electrons This gives an indication of the dynamic range the camera is capable of when compared to the readout noise but for most astronomers this figure of merit is not all that important You will rarely takes images that fill the pixels to the maximum level except for stars in the field of view Low level nebulosity will almost always be well below saturation While integrating longer would cause more build up of cha
7. with smaller pixels takes longer to digitize and download than Low resolution with larger pixels The cameras support High Medium Low and Auto resolution modes The Auto mode is optimized for the Focus command It automatically switches between Low resolution for Full frame mode to provide fast image acquisition and High resolution for Planet mode to achieve critical focus While Auto resolution is selected all images acquired using the GRAB command will be high resolution 3 9 3 Track and Accumulate An automatic Track and Accumulate mode SBIG patented is available in CCDOPS which simplifies image acquisition for the typical amateur with an accurate modern drive These drives employing PEC or PPEC technology and accurate gears only need adjustment every 30 to 120 seconds With Track and Accumulate the software takes multiple exposures and automatically co registers and co adds them The individual exposures are short enough such that drive errors are not objectionable and the accumulated image has enough integrated exposure to yield a good signal to noise ratio Operationally the camera will take an exposure determine the position of a preselected star co register and co add the image to the previous image and then start the cycle over again The software even allows making telescope corrections between images to keep the object positioned in the field of view The resulting exposure is almost as good as a single long exposure depending on
8. 32 Section 2 Introduction to CCD Cameras small pixels which are displayed on your computer screen to form an image Each pixel is displayed as a shade of gray or in some cases a color corresponding to a number which is produced by the electronics and photo sensitive nature of the CCD camera However electronic images differ from photographic images in several important aspects In their most basic form electronic images are simply groups of numbers arranged in a computer file in a particular format This makes electronic images particularly well suited for handling and manipulation in the same fashion as any other computer file An important aspect of electronic imaging is that the results are available immediately Once the data from the camera is received by the computer the resulting image may be displayed on the screen at once While Polaroid cameras also produce immediate results serious astrophotography ordinarily requires hypersensitized or cooled film a good quality camera and good darkroom work to produce satisfying results The time lag between exposure of the film and production of the print is usually measured in days With electronic imaging the time between exposure of the chip and production of the image is usually measured in seconds Another very important aspect of electronic imaging is that the resulting data are uniquely suited to manipulation by a computer to bring out specific details of interest to the observer In a
9. 5 mm 375 x 242 23 x 27 w ST 7E XE KAFO401E 6 9 x 4 6 mm 765 x 510 9x9u ST 8E XE KAF1602E 13 8 x 9 2 mm 1530 x 1020 9x9u ST 9E XE KAFO0261E 10 2x10 2mm 512x512 20 x 20 u ST 10E XE XME KAF3200E 14 9x10 0mm 2184x1472 6 8 x 6 8 u ST 1001E KAF1001E 24 6x24 6mm 1024x1024 24x24 u ST 2000XM KAI2000M_ 11 8 x 8 9mm 1600 x 1200 7AX7 AU Table 2 1 Camera CCD Configurations The CCD is cooled with a solid state a thermoelectric TE cooler The TE cooler pumps heat out of the CCD and dissipates it into a heat sink which forms part of the optical head s mechanical housing In the ST 7XE ST 8XE ST 9XE ST 10XE ST IOXME and ST 2000XM cameras this waste heat is dumped into the air using a new heat exchanger and a small fan The heat exchanger is also capable of water circulation for additional efficiency if needed in hot climates An inlet and outlet are provided at the back of the camera head for passing water through the heat exchanger Only a very small flow is required and an ordinary aquarium pump is sufficient if it will pull the flow up the length of tubing you might require at your installation An optional 110VAC pump and tubing are also available from SBIG Since the CCD is cooled below 0 C some provision must be made to prevent frost from forming on the CCD The ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM have the CCD TE Cooler mounted in a windowed hermetic chamber sealed with an O Ring The hermetic chamber does not need to be evacua
10. Desiccant This section describes the regeneration procedure for the desiccant used in the ST 7XE 8XE OXE 10XE ST 1OXME and ST 2000XM The desiccant absorbs moisture in the CCD chamber lowering the dew point below the operating temperature of the cooled CCD thus preventing the formation of frost The desiccant is contained in a small cylindrical plug that screws into the chamber from the rear In normal operation the useful life of the desiccant is over a year If the CCD chamber is opened often the desiccant should be regenerated when frosting is noticed Follow the procedure below to regenerate the desiccant 1 Unscrew the brass desiccant container from the rear of the camera and remove the O ring 2 Plug the resulting hole by screwing in the supplied bolt or plug 2 or 3 turns Finger tight is adequate Don t put a wrench on it 3 Heat the desiccant container in an oven at 350 F 175 deg C for 4 hours The solder used to seal the can melts at 460 degrees F so be sure to stay at least 50 degrees below this number Preheating the oven to avoid hot spots is advised 4 Replace the desiccant container into the rear of the camera being careful to reinstall the O ring and insure that it does not get pinched 5 Expect the camera to take an hour or two to reach the frost free state If it does seem to frost and you need to capture images reduce your cooling to the zero degree C range the CCD dark current will still be quite low
11. FLAT FLATXXXX blank extension Track list file TRACK XXXXXXXX TRK Combined flat field COMBINED FLAT FLATXXXX C Flat field corrected image CORRECTED IMAGE XXXXXXXX F 5 8 Tracking Functions The CCDOPS software allows your ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM to be used as an autoguider or self guided imager It does not function as a stand alone autoguider like the ST 4 but instead requires using a PC to perform the function These cameras have considerably better sensitivity than the ST 4 Page 56 Section 5 Advanced Imaging Techniques CCD autoguiders alleviate you from having to stare down the eyepiece for hours at a time while guiding astrophotographs They are not the end all cure all approach to telescope mechanical problems though You still need a good polar alignment and a rigid mount between the guide scope and the main scope or you need to use an off axis guider with all its inherent difficulties A good declination drive free of backlash is desirable although not absolutely necessary Finally modern drive correctors with periodic error correction PEC or permanent periodic error correction PPEC will ease the difficulty of achieving good results The moral of the story is don t count on the CCD autoguider to fix all your problems The better the drive the better results you will obtain Using the CCD as an autoguider requires interfacing the CPU s relay port to your hand controller as
12. Filter Wheel CFW 8A directly attached ST 7 8 9 10 2000 to camera body Page 34 Section 3 At the Telescope with a CCD Camera 3 At the Telescope with a CCD Camera This section describes what goes on the first time you take your CCD camera out to the telescope You should read this section throughout before working at the telescope It will help familiarize you with the overall procedure that is followed without drowning you in the details It is recommended you first try operating the camera in comfortable well lit surroundings to learn its operation 3 1 Step by Step with a CCD Camera In the following sections we will go through the steps of setting up and using your CCD camera The first step is attaching the camera to the telescope The next step is powering up the camera and establishing a communication link to your computer Then you will want to focus the system find an object and take an image Once you have your light image with a dark frame subtracted you can display the image and process the results to your liking Each of these steps is discussed in more detail below 3 2 Attaching the Camera to the Telescope ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM cameras are similar in configuration The CCD head attaches to the telescope by slipping it into the eyepiece holder or attaching it via t threads A fifteen foot cable runs from the head to the host computer s USB port The camera is powered by a desktop power su
13. Hardware Wizard Page 16 8 Section 1 Introduction If you have any question about whether the drivers were installed correctly open the Device Manager tab of the System Control Panel Click the View devices by type button and expand the Universal Serial Bus controllers section by clicking the to the left You should see something like the dialog below where we have highlighted the SBIG USB Camera in red outline System Properties ki General Device Manager Hardware Profiles Performance f View devices by type C View devices by connection fy Mouse Up Multifunction adapters coe Network adapters fl Ports COM amp LPT coe Sound video and game controllers ce W System devices z Universal Seral Bus controllers f Intelli 2807 44 USE Universal Host Controller Sep SBIG USB Camera oles USB 2 0 Root Hub ff USE Root Hub USB Root Hub USB Root Hub Vid PCI to USB Enhanced Host Controller Vid Tech 3038 FCI to USB Universal Host Controller Vid Tech 3038 FCI to USB Universal Host Controller Properties Refresh Remove Print Cancel Page 17 Section 1 Introduction 1 2 2 3 Add New Hardware Wizard for Windows 2000 Users 1 With the camera disconnected from the computer plug in the power to the camera and if your power supply has a power switch turn on the power to the camera 2 Plug the camera into the computer with the supplied USB cable The computer will t
14. affect the average user is described in the following paragraphs CCD Used TC 211 TC 237 TC 255 TC 237 TC 237 KAFO401E KAF1602E KAFO0261E KAF3200E KAFIOO1E KAI2000M Number of Pixels 192 x 164 657 x 495 320 x 240 657 x 495 320 x 200 765 x 510 1530 x 1020 512 x 512 2184 x 1472 1024 x 1024 1600 x 1200 Pixel Dimensions 13 75 x lou 74x74 u 10x 10u TAxT4u 14 8x 14 8 u 9x9u 9x9u 20x 20 u 6 8 x 6 8 uU 24x 24 u TAXTAU Table 4 3 CCD Differences Array Dimension 2 6 x 2 6 mm 4 9x 3 7mm 3 2x2 4mm 4 9x 3 7 mm 4 7 x 3 0 mm 6 9 x 4 6 mm 13 8 x 9 2 mm 10 2 x 10 2 mm 14 9 x 10 0 mm 24 6 x 24 6 mm 11 8 x 9 0 mm Read Noise 12e7 rms 12e rms 20e7 rms 15e7 rms 17e7 rms 15e rms 15e rms 13e rms l le rms 16e rms 15e rms Full Well Capacity 150K e7 20Ke 50Ke7 20Ke 20Ke 50 1 00Ke bl 50 100Ke 180Ke 77Ke 180Ke 45Ke Number of Pixels The number of pixels in the CCD affects the resolution of the final images The highest resolution device is best but it does not come without cost Larger CCDs cost more money and drive the system costs up They are harder to cool require more memory to store images take longer to readout etc With typical PC and Macintosh computer graphics resolutions the CCDs used in the SBIG cameras offer a good trade off between cost and resolution matching the computer s capabilities well Pixel Dimensions The size of the individual p
15. and ST 2000XM have regulated temperature control you may prefer to take and save separate dark images building up a library at different temperatures and exposure times and reusing them on successive nights At the start it s probably easiest to just take the dark frames when you are taking the image Later as you get a feel for the types of exposures and setpoint temperatures you use you may wish to build this library of dark frames 3 7 Displaying the Image The image can be displayed on the computer screen using the graphics capability of your PC Auto contrast can be selected and the software will pick background and range values which are usually good for a broad range of images or the background and range values can be optimized manually to bring out the features of interest The image can also be displayed as a negative image or can be displayed with smoothing to reduce the graininess Once displayed the image can be analyzed using crosshairs or can be cropped or zoomed to suit your tastes Page 38 Section 3 At the Telescope with a CCD Camera 3 8 Processing the Image If not done already images can be improved by subtracting off a dark frame of equal exposure You will typically do this as part of the Grab command although it can also be done manually using the Dark Subtract command By subtracting the dark frame pixels which have higher dark current than the average i e hot pixels are greatly suppressed and the displ
16. co add several shorter images The dual CCD design allows the guiding CCD access to the large aperture of the main telescope without the inconvenience of off axis radial guiders Not only are guide stars easily found but the problems of differential deflection between guide scope and main scope eliminated Track and Accumulate is another SBIG patented process US 5 365 269 whereby short exposures are taken and added together with appropriate image shifts to align the images It is supported by the ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM camera software but will generally not produce as good as results as self guiding where the corrections are more frequent and the accumulated readout noise less It is handy when no connection to the telescope drive is possible and also works best on cameras with larger pixels like the ST 9XE or for cameras with smaller pixels in binned mode For cameras with smaller pixels imaging in high resolution mode such as the ST 7XE ST 8XE ST 10XE ST 1OXME and ST 2000XM SBIG is proud to make self guiding available to the amateur making those long exposures required by the small pixel geometry easy to achieve 2 5 Electronic Imaging Electronic images resemble photographic images in many ways Photographic images are made up of many small particles or grains of photo sensitive compounds which change color or become a darker shade of gray when exposed to light Electronic images are made up of many Page
17. discussed in section 4 4 and then training the CCD system on your telescope This is done with the Calibrate Track command Focus your system and then find and center on a moderately bright calibration star 1000 to 20 000 peak counts will do without any nearby neighboring stars of similar brightness Then execute Calibration command It takes a sequence of five images In the first image it determines the pixel position of the calibration star In the four subsequent images the software in sequence activates each of the telescope s four correction directions measuring the displacement of the calibration star From this calibration information the software is able to calculate a precise correction when the guide star moves away from its intended position At the start you should pick a calibration star with roughly the same declination as the intended object since the telescope s correction speeds vary with declination As you get used to the tracking functions you can calibrate on a star near the celestial equator and have the software adjust for different declinations for you The tracking functions in CCDOPS are accessed through the Track menu The Calibrate Track command as described above is used to calibrate your telescope s drive corrector Once that is done the Track command which you would use for autoguiding astrophotographs allows you to select a guide star in the field of view and then repeatedly takes images measuring the guide
18. disk It is only necessary to have a camera connected when you take new images Once the COM link has been established you may need to set the camera s setpoint temperature in the Camera Setup command The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM power up regulating to whatever temperature the CCD is at which in this case will be the ambient temperature Use the Camera Setup command and choose a setpoint temperature approximately 30 C below the ambient temperature Type in the setpoint set the temperature control to active and hit ENTER 3 4 Focusing the CCD Camera Focusing a CCD camera can be a tedious operation so a few hints should be followed Before using the software to focus the camera the first time you should place a diffuser such as scotch tape or ground glass at the approximate location of the CCD s sensitive surface behind the Page 36 Section 3 At the Telescope with a CCD Camera eyepiece tube and focus the telescope on the moon a bright planet or a distant street lamp This preliminary step will save you much time in initially finding focus The approximate distance behind the eyepiece tube for each of our CCD cameras is listed in Table 3 1 below Camera Distance ST 7 8 9 10XE 0 92 inch ST 2000XM 0 92 inch Diffuser l Back Focus Distance from Table 3 1 To achieve fine focus insert the CCD head into the eyepiece tube taking care to seat it and then enter the CCDOPS FOCUS mode The Foc
19. g Universal Serial Bus controllers K Generic USB Hub Intel R S2801E6 USB Universal Host Controller 24D2 Intel R S2801E6 USB Universal Host Controller 24D 4 se 82601EB USB Universal Host Controller 24D E SB Universal Host Controller 24DE g E E i Standard Enhanced PCI to USB Host Controller LSB Root Hub gt LSB Root Hub gt U56 Root Hub LSB Root Hub USB Root Hub Page 12 Section 1 Introduction 1 2 2 2 Add New Hardware Wizard for Window 95 98 Me Users 1 With the camera disconnected from the computer plug in the power to the camera and if your power supply has a power switch turn on the power to the camera 2 Plug the camera into the computer with the supplied USB cable The computer will then present you with the Found New Hardware Wizard shown below Add New Hardware Wizard This wizard searches for new drivers for USB Device A device diver is a software program that makes a hardware device work Click the Next button 3 Click Search for the best driver then click the Next button as shown below Add New Hardware Wizard What do you want Windows to do nunnnnnnNNNNNNNNNANNNNNNNNNNNANNNNNNANANNNNNANENNNNNNNNNNNNNENNNMANENENNNANENENNNENNNENENENENENENENNN Search for the best driver for your device Recommended C Display a list of all the drivers in a specific location 0 you can select the driver you want lt Back Cancel
20. inch or larger draw tube sliding into the telescope s focus mechanism The placement of the preamplifier and readout electronics close to the CCD is necessary to achieve good noise performance The Microcontroller is housed in the rear of the Optical Head along with the interface logic to the PC and Telescope 4 2 Connecting the Power The desktop power supply is designed to run off voltages found in most countries 90 to 240 VAC In the field however battery operation may be the most logical choice In that case you need to use the optional 12V power supply or a 12VDC to 110 VAC power inverter 4 3 Connecting to the Computer The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM CCD Cameras are supplied with a 15 foot cable to connect the system to the host computer The connection is between the camera and the Host Computer s USB port If it is necessary or desirable to extend the distance between the camera and the computer third party USB extenders such as the Ranger made by Icron fhitp fwww icron com may be used for remote operation up to 500 meters 4 4 Connecting the Relay Port to the Telescope The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM camera systems can be used as autoguiders where the telescope s position is periodically corrected for minor variations in the RA and DEC drives The host software functions as an autoguider in three modes the Track mode the SBIG patented Track and Accumulate mode
21. mouse to move the crosshair around in the image and see the pixel values e Close the crosshairs and try inverting the image Click the Invert item in the Contrast window e Try the photo display mode Use the Photo Mode command in the Display menu Click the mouse to return to the menus e Load up the other sample images and display them using the photo display mode You have to close any existing image first e If you find that the display is too dark or bright try setting Auto Contrast in the Contrast window or adjust the background and range parameters to achieve the best display You may have to hit the Apply button in the Contrast window to see changes in the Background and Range 1 2 5 Capturing Images with the CCD Camera Unfortunately there really aren t many shortcuts you can take when using the CCD camera to capture images The instructions below refer you to various sections of the manual e Find some relatively bright object like M51 the Ring Nebula M57 or the Dumbbell Nebula M27 refer to section 3 5 e Take a1 minute exposure using the Grab command with the Dark frame option set to Also refer to Section 3 6 e Display the image refer to Section 3 7 e Process the image refer to Section 3 8 You can use the SBIG Test Lens to take indoor test exposures and get familiar with the camera operation Also if you happened to have purchased a camera lens adapter for your CCD Camera you can also use that to take t
22. scientific work such as variable star monitoring and position determination 2 2 How CCD Detectors Work The basic function of the CCD detector is to convert an incoming photon of light to an electron which is stored in the detector until it is read out thus producing data which your computer can display as an image It doesn t have to be displayed as an image It could just as well be displayed as a spreadsheet with groups of numbers in each cell representing the number of electrons produced at each pixel These numbers are displayed by your computer as shades of eray for each pixel site on your screen thus producing the image you see How this is accomplished is eloquently described in a paper by James Janesick and Tom Elliott of the Jet Propulsion Laboratory Imagine an array of buckets covering a field After a rainstorm the buckets are sent by conveyor belts to a metering station where the amount of water in each bucket is measured Then a computer would take these data and display a picture of how much rain fell on each part of the field Ina CCD the raindrops are photons the buckets the pixels the conveyor belts the CCD shift registers and the metering system an on chip amplifier Technically speaking the CCD must perform four tasks in generating an image These functions are 1 charge generation 2 charge collection 3 charge transfer and 4 charge detection The first operation relies on a physical process known as the pho
23. signal to noise ratio combined with faster digitization and download times makes Medium Resolution Mode ideal for finding and centering dim objects and for imaging most objects Additionally a Low resolution mode is provided which bins the CCD 3x3 before readout Low resolution mode is sensational for displaying faint nebulosity Page 54 Section 5 Advanced Imaging Techniques with short exposure times In Auto Resolution Mode the camera and software will always use High Resolution for all imaging and display functions except when you are in Full Frame Focus Mode It will then automatically switch to Low Resolution Mode If you further select Planet Mode for focusing the camera will switch back to High Resolution on the selected box area The small pixel size is best for critical focusing Planet mode will result in fast digitization and download times since only a small portion of the frame is read out In general you should pick a binning mode that yields stars with two to three pixels full width at half maximum This is easily measured by using the crosshairs to determine the peak brightness of a relatively bright star and determining the number of pixels between the 50 values on either side of the peak More than 3 pixels per stellar halfwidth merely wastes sensitivity without improved resolution 5 7 Flat Fielding Track and Accumulate Images This section gives the step by step procedure for flat field correcting images taken using th
24. the exposure used and sky conditions The great sensitivity of the CCD virtually guarantees that there will be a usable guide star within the imaging CCD s field of view This feature provides dramatic performance for the amateur enabling long exposures with minimal setup 3 9 4 Autoguiding and Self Guiding The CCDOPS software allows the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM cameras to be used as autoguiders and self guiders through the commands in the Track menu While these systems are not stand alone like the ST 4 but require a host computer they can accurately guide long duration astrophotographs and CCD images with equal or superior accuracy Their sensitivity is much greater than an ST 4 and the computer display makes them easier to use When functioning as an autoguider the CCD camera repeatedly takes images of a guide star measures the star s position to a fraction of a pixel accuracy and corrects the telescope s position through the hand controller While autoguiding alleviates the user of the tedious task of staring through an eyepiece for hours at a time it is by no means a cure to telescope drive performance All the things that were important for good manually guided exposures still exist including a good polar alignment rigid tubes that are free of flexure and a fairly good stable mount and drive corrector Remember that the function of an auto guider is to correct for the small drive errors and long term dri
25. 0 Index 78 nosepiece 37 observatory 45 optical head 37 45 optical head orientation 38 O ring 28 PC 29 PC Setup Command 38 PEC drive correctors 42 59 photometric measurements 68 Photometry def 68 pixel nonuniformity 41 pixel size 31 50 Pixel Size def 68 pixel uniformity 30 planet mode 41 Planet mode def 68 planets 25 39 52 55 POWER connector 37 power supply 29 37 power supplyr 45 PPEC drive correctors 42 59 preamp 28 45 printing images 33 63 push to make switch modification 47 push to make break switch modification 47 Quantum Efficiency def 68 range parameter 40 readout electronics 45 noise 51 Noise def 69 register 26 regenerating desiccant 73 RELAYS connector 45 59 resolution 31 42 56 Resolution def 69 Response factor def 69 Right Ascension 37 45 59 66 Saturation def 69 scribing the eyepiece 40 seeing 31 39 42 52 Seeing def 70 self guiding 45 separations 41 setup 37 SGS Self Guided Spectrograph 62 sharpen 41 shutter 28 signal to noise ratio 44 51 sky background 25 42 smoothing 41 snapshot 46 software 49 63 spectral range 25 spectrograph 62 Status Window 38 Link field 38 stellar magnitude 41 stellar temperature 41 super pixel 41 taking images 40 TE cooler 29 TE Cooler 28 TE Cooler def 70 Technical Support 63 telescope 31 37 40 42 Telescope connector 71 72 telescope hand controller 40
26. 4 93 x 3 71 mm 6 17 mm 8 2 x 6 2 arcminutes ST 5C 3 20 x 2 40 mm 4 00 mm 5 6 x 4 2 arcminutes ST 237A 4 93 x 3 71 mm 6 17 mm 8 2 x 6 2 arcminutes STV 4 74 x 2 96 mm 5 58 mm 8 2 x 5 1 arcminutes ST 7XE 6 89 x 4 59 mm 8 28 mm 11 9 x 7 9 arcminutes ST 8XE 13 8 x 9 18 mm 16 6 mm 23 8 x 15 8 arcminutes ST 9XE 10 2 x 10 2 mm 14 4 mm 17 6 x 17 6 arcminutes ST 10XE XME 14 9 x 10 0 mm 17 9 mm 25 1 x 16 9 arcminutes ST 1001E 24 6 x 24 6 mm 34 8 mm 41 5 x 41 5 arcminutes ST 2000XM 11 8 x 9 0 mm 14 8 mm 20 0 x 15 0 arcminutes 35mm Film 36 x 24 mm 43 mm 62 x 42 arcminutes Table 2 2 CCD Array Dimensions 2 4 6 Guiding Any time you are taking exposures longer than several seconds whether you are using a film camera or a CCD camera the telescope needs to be guided to prevent streaking While modern telescope drives are excellent with PEC or PPEC they will not produce streak free images without adjustment every 30 to 60 seconds The ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM allow simultaneous guiding and imaging called self guiding US Patent 5 525 793 This is possible because of the unique design employing 2 CCDs One CCD guides the telescope while the other takes the image This resolves the conflicting requirements of short exposures for guiding accuracy and long exposures for dim objects to be met something that is impossible with single CCD cameras Up to now the user either had to set up a separate guider or use Track and Accumulate to
27. IG provides software for the ST 7XE ST 8XE ST 9XE ST 10XE ST 10OXME and ST 2000XM cameras for the IBM PC and Compatible computers running Windows 95 98 2000 Me NT XP The software allows image acquisition image processing and auto guiding with ease of use and professional quality Many man years and much customer feedback have gone into the SBIG software and it is unmatched in its capabilities 2 4 CCD Special Requirements This section describes the unique features of CCD cameras and the special requirements that CCD systems impose 2 4 1 Cooling Random readout noise and noise due to dark current combine to place a lower limit on the ability of the CCD to detect faint light sources SBIG has optimized the ST 7XE ST 8XE ST OXE ST 10XE ST 10XME and ST 2000XM to achieve readout noises below 20 electrons rms for two reads light dark This will not limit most users The noise due to the dark current is equal to the square root of the number of electrons accumulated during the integration time For these cameras the dark current is not significant until it accumulates to more than 280 electrons Dark current is thermally generated in the device itself and can be reduced by cooling All CCDs have dark current which can cause each pixel to fill with electrons in only a few seconds at room temperature even in the absence of light By cooling the CCD the dark current and corresponding noise is reduced and longer exposures are possible In fa
28. LowOpen Drain 12 Volts Out 100mA max shared with I2C AUX 5 Volts Out 300 mA max shared with I2C AUX Chassis Ground Table A1 Telescope Connector 1 2 3 4 5 6 7 8 9 ep 3 2 A 2 Connector Pinouts for the power jack Pin Number Function Earth Ground DC Ground 12V DC 100mA No contact 12V DC 500mA 5V DC 2A Table A2 Power Connector Power Jack A 3 Connector Pinouts for the I2C AUX port Pin Number Function 5V DC 300 mA max shared with AO7 CFW8 No Contact Serial Clock Serial Data Signal Ground No Contact No Contact 12V DC 100mA max shared with AO7 CFW8 3 3V DC 500mA max Chassis Ground Table A3 I2C Accessory Port YO COON DOF WN PR ep a 6 The Open Drain outputs can sink 100 mA maximum Page 69 Appendix A Connector Pinouts A 4 SBIG Tracking Interface Cable TIC 78 Many of the newer telescopes have a phone jack connector on the drive corrector for connecting directly to the ST 7XE 8XE 9XE 10XE ST 10XME and ST 2000XM Camera s Telescope Port These include the Celestron Ultima Losmandy CG11 and Meade LX 200 You can interface these telescopes to the Telescope port with our TIC 78 Tracking Interface Cable or you can make your own cable Figure A1 below shows the pinouts on some of these telescopes Hand Controller Modular Phone Button Wire Color Telescope Port Pin Special White None Common Black Left Red Down Green Up Yellow Right Blu
29. Page 71 Appendix C Capturing a Good Flat Field C Appendix C Capturing a Good Flat Field This appendix describes how to take a good flat field A good flat field is essential for displaying features little brighter than the sky background The flat field corrects for pixel non uniformity vignetting dust spots affectionately called dust doughnuts and stray light variations If the flat field is not good it usually shows up as a variation in sky brightness from on side of the frame to the other C 1 Technique The first consideration in capturing a flat field is to use the telescope CCD combination in exactly the configuration used to collect the image This means you probably have to capture the flat field at the telescope Do not rotate the head between image and flat field since the vignetting is usually slightly off center Do not be tempted to build a little LED into the telescope or camera for doing flat fields it doesn t work at all The dust debris shadows would be different Arrange a light source such as a flashlight two white cards the telescope and CCD as shown in Figure D 1 Figure D 1 Flat Field Geometry Telescope CCD Flat White Surface Flat white C gisshlisie Surface The key aspects of this geometry are that the reflection off two diffuse surfaces is used and the large flat surface is square to the illumination from the small flat surface When we do this the first flat surface is typically a whi
30. SBIG ASTRONOMICAL INSTRUMENTS Operating Manual CCD Camera Models ST 7XE XME ST 8XE ST 9XE ST 10XE XME and ST 2000XM XCM With High Speed USB Interface Santa Barbara Instrument Group 147A Castilian Drive Santa Barbara CA 93117 Phone 805 571 7244 e Fax 805 571 1147 Web lt www sbig com gt e Email lt sbig sbig com gt Note This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures e Reorient or relocate the receiving antenna e Increase the separation between the receiver and the equipment e Connect the equipment into an outlet on a circuit different from that to which the receiver is connected e Consult the dealer or an experienced radio TV technician for help Shielded I O cables must be used when operating
31. a clear image with good detail Of course longer exposures are possible and desirable depending on your telescope s tracking ability or your desire to guide Once you have determined the longest exposure possible with your particular drive error try Track and Accumulate exposures of a duration less than your measurable error We have found that exposures of thirty seconds to two minutes are best depending on the focal length of telescope one is using With the self guiding feature of the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM one can take long integrations while the internal tracking CCD guides the telescope We highly recommend that you initially pursue deep sky imaging with a fast telescope or focal reducer to produce a final F number of F 6 3 or faster at the CCD The sensitivity advantage is considerable 5 3 Terrestrial Imaging An optional accessory for the SBIG cameras is the camera lens adapter These accessories are made to accommodate most popular camera models You may attach a camera lens in place of your telescope and use the CCD camera for very wide angle images of the night sky or for terrestrial views in daylight Begin with a tenth second exposure at f 16 for scenes at normal room light and adjust as necessary for your conditions Page 53 Section 5 Advanced Imaging Techniques 5 4 Taking a Good Flat Field If you find that flat field corrections are necessary due to vignetting effects CCD sensitivity v
32. abilities can be added to the camera by replacing the loader driver New Boot sequence LED flashes and fan comes on when firmware upload is complete LED flashes when initializing shutter Mechanical electronic design work to reduce shutter errors and stray light TC237 autoguider CCD added to the ST 8XE ST 9XE ST 10XE and ST 10XME Premier software CCDSoftV5 and TheSky included with each camera CCDOPS version 5 camera control software included with major improvements o Support for USB cameras Support for Ethernet Ethernet to Parallel for parallel cameras Read FITS files Save in several formats including ASCII format that imports to Excel Multiple images open at once New universal drivers VVVVV VV VV VV V O O O OPO Page 3 Section 1 Introduction Works with all 32 bit Windows OS 95 98 Me NT 2000 XP Version 5 Gold Icon can co exist with Version 4 Black Icon Focus Mode Dialog has big numbers for peak brightness to aid focusing Added 1xN 2xN and 3N readout modes to ST 7 8 9 10 1001 Magnified preview in crosshairs window Sharpen preview in contrast dialog Dockable Icon bar O O O 0 0 0 0 1 1 Getting Started This manual describes the ST 7XE XME ST 8XE ST 9XE ST 10XE XME and ST 2000XM XCM CCD Camera Systems from Santa Barbara Instrument Group The first section contains USB driver installation instructions The USB driver installation process must be completed by anyone installing an SBIG USB ca
33. alifornia Institute of Technology CCD Advanced Development Group Page 26 Section 2 Introduction to CCD Cameras TH Cooler Tracking CCD Wicro loc controller Drivere Telescope Interface Imaging COD Host Computer USB Interface Figure 2 2 CCD System Block Diagram As you can see from Figure 2 2 the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM are completely self contained Unlike our previous products the ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM contain all the electronics in the optical head There is no external CPU like the ST 5C ST 237 ST 6 and STV At the front end of any CCD camera is the CCD sensor itself As we have already learned CCDs are a solid state image sensor organized in a rectangular array of regularly spaced rows and columns The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM use two CCDs one for imaging Kodak KAF series and one for tracking TI TC211 or TC237 Page 27 Section 2 Introduction to CCD Cameras Table 2 1 below lists some interesting aspects of the CCDs used in the various SBIG cameras Array Number of Camera CCD Dimensions Pixels Pixel Sizes TC211 Tracking CCD TC211 2 6 x 2 6 mm 192 x 164 13 75 x 16 u TC237 Tracking CCD TC237 4 9x3 7 mm 657 x 495 7TAX7 AU ST 5C TC255 3 2 x 2 4mm 320 x 240 10x10 u ST 237A TC237 4 9x3 7 mm 640 x 480 7AX7 AU STV STV Deluxe TC237 4 7 x 3 0 mm 320 x 200 14 8 x 14 8 u ST 6B TC241 8 6 x 6
34. analysis Tucson AZ 85719 spectroscopy Voice 520 323 8600 Fax 520 822 1435 E mail Sales E mail Support Axilone Multimedia Image processing camera 18 ch des Ajoncs 31470 Saint Lys FRANCE control Phone 33 5 34472052 Fax 33 5 34 47 10 20 E mail M S B di Fabio Cavicchio Via Romea Vecchia 67 Astroart Image processing Classe 48100 Ravenna RA P IVA 01379350398 software and camera TEL FAX 39 0544 473589 Mobile 39 0339 2739548 control FITS viewer E Mail msbsoftware tin it Web site http www msb astroart com New Astronomy Press Ron Wodaski The New Book Basics of CCD PO Box 1766 Duvall WA 98019 Astronomy Imaging background and E mail kupport newastro com techniques FAX 425 844 1535 Web site http www newastro com The Minor Planet Observer Brian Warner Minor Planet Astrometry Minor planet e mail brianw_mpo compuserve com Observer searches Web site http www muinorplanetobserver com software Page 75 Appendix E Third Party Vendors Supporting SBIG Products Bruce Johnston Computing MexaFix Image processing 7124 Cook Rd Software Swartz Creek MI 48473 U S A Phone 810 635 9191 Fax 1 810 750 1761 Web site http members aol com bjohns7764 Phase Space Technology Astra Image Image Processing Phone 61 3 9735 2270 Fax 61 3 9739 4996 Software Web site http www phasespace com au E mail Support E mail General E mail Orders Steve Mandel Mandel Wide Nikon lens ad
35. and the SBIG patented Self Guided mode except for the ST 1001E In the Track mode and Self Guided mode the host software corrects the telescope as often as once every second to compensate for drift in the mount and drive system The host software and the CCD camera operate in tandem to repeatedly take exposures of the designated guide star calculate its position to a tenth of a pixel accuracy and then automatically activate the telescope s controller to move the star right back to its intended position It does this tirelessly to guide long duration astrophotographs In the Track and Accumulate mode the software takes a series of images and automatically co registers and co adds the images to remove the effects of telescope drift Page 43 Section 4 Camera Hardware Typically you would take ten 1 minute snapshots to produce an image that is comparable to a single 10 minute exposure except that no guiding is required The reason no guiding is required is that with most modern telescope mounts the drift over the relatively short 1 minute interval is small enough to preserve round star images a feat that even the best telescope mounts will not maintain over the longer ten minute interval The Track and Accumulate software does allow correction of the telescope position in the interval between snapshots to keep the guide star grossly positioned within the field of view but it is the precise co registration of images that accounts for the streakl
36. apter for Hidden Valley Observatory Field Adapter SBIG color filter wheel 1425 Hidden Valley Rd Soquel CA 95073 Dr Brady Johnson Johnson Pentax Olympus and E mail bradydjohnson rogers com Wide Field Minolta lens adapters for Web site Adapter SBIG color filter wheel http members roger idvdiohn lefielc Astro Physics Inc APO 4 to 6 APO refractors 11250 Forest Hills Road Rockford IL 61115 U S A Refractors and GOTO mounts Phone 815 282 1513 Fax 815 282 9847 and mounts Authorized SBIG OEM Web site RC Optical Systems Ritchey RC Telescopes and Brad Ehrhorn Chretien accessories for CCD 3507 Kiltie Loop Flagstaff AZ 86001 telescopes imaging Authorized Tel 928 773 7584 SBIG OEM E mail info rcopticalsystems com Web site http www rcopticalsystems com index html Astro Works Corporation Centurion 18 18 F 2 8 telescope made P O Box 699 Aguila Arizona 85320 telescope specifically for CCD Tel 928 685 2422 imaging Authorized Web site http www astroworks com SBIG OEM Disclaimer Mention is made of third party vendors in this section as a courtesy only These vendors are independent companies and or individuals SBIG does not endorse or support any particular company product or service by virtue of mentioning them in this section SBIG is not responsible for the use of any product or service mentioned in this section that is not manufactured or made by SBIG Page 76 A D converter 28 49 accessor
37. ariations or for more accurate measurements of star magnitudes try either taking an image of the twilight sky near the horizon or take an image of a blank wall or neutral grey card The Kodak CCDs may have a low contrast grid pattern visible in the sky background A flat field will eliminate this Finding areas of the sky devoid of stars is very difficult after twilight Therefore you should take flat field images of the night sky after sunset but long before you can see any stars If this is not possible take an image of a featureless wall or card held in front of the telescope However if using this second method be sure that the wall or card is evenly illuminated Appendix D describes how to do this You will know if the flat field is good if the sky background in your images has little variation across the frame after flat fielding displayed using high contrast a range of 256 counts is good for showing this If you plan on flat fielding Track and Accumulate images you should also refer to section 6 8 Since the same flat field is added to itself a number of times be sure that you do not saturate the flat field image by starting with pixel values too high Typically try to keep the pixel values between 10 to 20 of saturation for this purpose For single flat field images try to keep the values to approximately 50 of saturation 5 5 Building a Library of Dark Frames The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM have regul
38. ated temperature control and therefore it is possible to duplicate temperature and exposure conditions on successive nights You can set the camera TE cooler temperature to a value comfortably within reach on your average night and then take and save on disk a library of dark frames for later use This is a good project for a rainy night We recommend you build a file of 5 10 20 40 and 60 minute dark frames at zero degrees Centigrade for a start Otherwise you will find yourself wasting a clear night taking hour long dark frames Note Dark frames taken the same night always seem to work better The adaptive dark subtract will help if the ambient temperature changes slightly 5 6 Changing the Camera Resolution The Camera Setup command allows you to select the resolution mode you wish to use for taking and displaying images The ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM cameras have High Medium Low and Auto modes The High Resolution mode is the best for displaying the greatest detail since it utilizes the maximum number of pixels for your particular camera The Medium Resolution Mode operates by combining 2x2 pixels giving the same field of view as High Resolution Mode but with 1 4 the resolution This results in significantly faster digitization and download times Also in Medium Resolution Mode with larger pixels and comparable readout noise there is a better signal to noise ratio for very dim diffuse objects This improved
39. ayed image appears much smoother Visibility of faint detail is greatly improved The CCDOPS program also supports the use of flat field frames to correct for vignetting and pixel to pixel variations as well as a host of other image processing commands in the Utility menu You can smooth or sharpen the image flip it to match the orientation of published images for comparison or remove hot or cold pixels 3 9 Advanced Capabilities The following sections describe some of the advanced features of SBIG cameras While you may not use these features the first night they are available and a brief description of them is in order for your future reference 3 9 1 Crosshairs Mode Photometry and Astrometry Using the crosshair mode enables examination of images on a pixel by pixel basis for such measurements as Stellar and Diffuse Magnitude and measurement of stellar positions The 16 bit accuracy of SBIG systems produces beautiful low noise images and allows very accurate brightness measurements to be made With appropriate filters stellar temperature can be measured In the crosshair mode you move a small cross shaped crosshair around in the image using the keyboard or the mouse As you position the crosshair the software displays the pixel value beneath the crosshair and the X and Y coordinates of the crosshair Also shown is the average pixel value for a box of pixels centered on the crosshair You can change the size of the averaging box from 3
40. bilize at the lowest temperature it can achieve Examine the camera temperature and reset the set point to 3 degrees C above the current temperature This 3 degree temperature margin will enable the camera to regulate the temperature accurately When using water cooling avoid the temptation to put ice in the water to get the camera even colder If colder water is used the head may fog or frost up depending on the dew point At the end of the evening stop the pump and raise the outlet hose above the camera to let all the water drain out of the system Blowing it out with gently pressure helps clear the water You can leave the hoses full of water but if a leak occurs while you re not there you may have a problem When packing the camera for a long time or at the end of summer disconnect the hoses and blow out the heat sink to allow the enclosed spaces to dry out and minimize long term corrosion Page 59 Section 6 Accessories for your CCD Camera 6 2 Tri color Imaging You can make splendid color images with your CCD camera by using the optional CFW 8 color filter wheel The CFW 8 attaches to the front of the CCD head and allows you to take images in red green and blue light of the same object When these images are aligned and processed a full color image results 6 3 Camera Lens Adapters and Eyepiece Projection Camera Lens adapters are available for the ST 7XE 8XE 9XE 10XE ST 10OXME and ST 2000XM The camera lens adapter a
41. by using the telescope drive motors to force a guide star to stay precisely centered on a single pixel of the CCD array The camera has four relays to control the drive corrector system of the telescope The CCD camera head is installed at the guide scope or off axis guider in place of a guiding eyepiece CCD The CCD Charged Coupled Device is a flat two dimensional array of very small light detectors referred to as pixels Each pixel acts like a bucket for electrons The electrons are created by photons light absorbed in the pixel During an exposure each pixel fills up with electrons in proportion to the amount of light entering the pixel After the exposure is complete the electron charge buildup in each pixel is measured When a pixel is displayed at the computer screen its displayed brightness is proportional to the number of electrons that had accumulated in the pixel during the exposure Dark Frame The user will need to routinely create image files called Dark Frames A Dark Frame is an image taken completely in the dark The shutter covers the CCD Dark Frames are subtracted from normal exposures light frames to eliminate fixed pattern and dark current noise from the image Dark Frames must be of the same integration time and temperature as the light frame being processed Dark Noise Dark Noise or Dark Current is the result of thermally generated electrons building up in the CCD pixels during an exposure The number of electrons d
42. ch activating the relay or pushing the hand controller button closes the Normally Open or Push to Make contact while at the same time the Normally Closed contact is wired in series with the switch activating the relay or pushing the hand controller button opens the Normally Closed or the Push to Break contact This type of switch modification is shown in Figure 4 2 below A Unmodified Push to Make Break Switch B Modified Push to Make Break Switch common C common switch normally open normally open normally closed Figure 4 2 Push to Make Break Modification normally closed The last type of hand controller that is moderately common is the resistor joystick In this joystick each axis of the joystick is connected to a potentiometer or variable resistor Moving the joystick handle left or right rotates a potentiometer varying the resistance between a central wiper contact and the two ends of a fixed resistor The relays can be interfaced to the joystick Page 45 Section 4 Camera Hardware as shown in Figure 4 3 below Essentially the relays are used to connect the wire that used to attach to the wiper to either end of the potentiometer when the opposing relays are activated A wiper B C potentiometer A Unmodified Joystick B Modified Joystick Figure 4 3 Joystick Modification A slight variation on the joystick modification is to build a complete joystick eliminator as shown in Figure 4 4 below Th
43. ct for roughly every 5 to 6 C of additional cooling the dark current in the CCD is reduced to half The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM have a single stage TE cooler efficient heat exchanger and water circulation capability A temperature sensing thermistor on the CCD mount monitors the temperature Earlier parallel models offered a cooling booster which used a second TE cooler but we feel that the new design provides similar performance without the need for a second power supply The micro controller controls the temperature at a user determined value for long periods As a result exposures hours long are possible and saturation of the CCD by the sky background typically limits the exposure time At 0 C the dark current in the ST 7XE ST 8XE and ST 10XE high resolution mode is only 60 electrons per minute The ST 9XE with bigger pixels has roughly 8 times this amount of dark current due largely to the larger pixel area but also due to the inherent higher bulk dark current in the devices The sky background conditions also increase the noise in images and in fact as far as the CCD is concerned there is no difference between the noise caused by dark current and that from sky background If your sky conditions are causing photoelectrons to be generated at the rate of 100 e pixel sec for example increasing the cooling beyond the point where the dark current is roughly half that amount will not improve the quality of t
44. ction 4 Camera Hardware From the telescope s point of view the different models offer differing fields of view for a given focal length or turned around to achieve the same field of view the different models require differing focal lengths Tables 4 4 and 4 5 below compare the fields of view for the cameras at several focal lengths and vice versa C8 8 10 LX200 10 3l 14 f 11 Field of Pixel Size Field of View Pixel Size Field of Pixel Size View arcsecs arcmins arcsecs View arcsecs Camera arcmins arcmins TC211 Tracking CCD 4 2x4 2 1 3x1 5 11 7x11 7 3 7x4 3 2 3x2 3 0 7x0 8 TC237 Tracking CCD 8 2x6 2 0 75x0 75 21 9x16 5 2 0x2 0 4 3x3 2 0 39x0 39 ST 5C 5 4x4 1 1 0x1 0 14 4x10 8 21x27 2 8x2 1 0 5x0 5 ST 237A 8 2x6 2 0 75x0 75 21 9x16 5 2 0x2 0 4 3x3 2 0 39x0 39 STV 8 0x5 0 1 5x1 5 21 6x13 5 4 0x4 0 4 0x2 5 0 75x0 75 ST 7XE 11 9x7 9 0 9x0 9 31 2x20 8 2 4x2 4 6 1x4 1 0 5x0 5 ST 8XE 23 8x15 8 0 9x0 9 62 4x41 6 2 4x2 4 12 2x8 2 0 5x0 5 ST 9XE 17 6x17 6 2 0x2 0 46 2x46 2 5 3x5 3 9 1x9 1 1 1x1 1 ST 10XE 25 1x16 9 0 7x0 7 67 0x45 2 1 8x1 8 13 0x8 8 0 36x0 36 ST 1001E 41 6x41 6 2 4x2 4 111x111 6 5x6 5 21 6x21 6 1 27x1 27 ST 2000XM 20 0x15 0 0 75x0 74 53 4x40 1 2 0x2 0 10 4x7 8 0 39x0 39 Table 4 4 Field of View Focal Length to fill 211 Focal Length Object Size Tracking CCD to fill ST 7XE Moon 0 5 275mm 11 inches 760mm 30 inches Jupiter 40 arcseconds 13000mm 510 inches 34000mm 1350 inches 3700mm 145 inches 3700
45. ction with the CCDSharp software stellar peak brightness can double and stellar half widths can shrink by 25 6 6 SGS Self Guided Spectrograph The SGS Self Guided Spectrograph takes the tedium out of spectroscopy by allowing you to image and guide the source on the tracking CCD while acquiring its spectra on the imaging CCD No more hunting around to place the object on the slit With the SGS you can measure galactic redshifts stellar classifications and determine nebular constituency This is another example of the value of a self guided camera like the ST 7XE 8XE 9XE 10XE ST 10XME and ST 2000XM Page 60 Section 6 Accessories for your CCD Camera 6 7 Third Party Products and Services There are numerous third party products and services available directed to the CCD user Appendix E mentions a few vendors who have supported SBIG products just to give you an idea of the ever increasing interest in this new technology 6 7 1 Windows Software Our CCDOPS version 5 software is compatible with Windows 95 98 2000 Me NT XP However many users also want additional image processing or analytical features not found in CCDOPS Therefore since January 2001 all SBIG cameras also include CCDSoftV5 which is a joint software development of SBIG and Software Bisque There are also several other commercial Windows programs available which include a stellar database telescope control for computerized telescopes like the Meade LX200 and CCD ca
46. d from other stars are preferred Once the star is selected the computer starts guiding the telescope When the telescope corrections settle down usually once the backlash is all taken up in the declination drive the user starts the exposure by striking the space bar The computer then integrates for the prescribed time while guiding the telescope and downloads the image for display A calibration star should be chosen that is relatively bright and isolated The calibration software can get confused if another star of comparable brightness moves onto the tracking CCD during a move The unit will self guide on much fainter stars Tests at SBIG indicate that the probability of finding a usable guide star on the tracking CCD is about 95 at F 6 3 in regions of the sky away from the Milky Way Ifa guide star is not found the telescope position should be adjusted or the camera head rotated by a multiple of 90 degrees to find a guide star We recommend that the user first try rotating the camera 180 degrees Rotating the camera will require recalibration of the tracking function Note CCDSoftV5 software allows SBIG cameras to calibrate and track in any orientation similar to the STV video autoguider 3 9 5 Auto Grab The Auto Grab command allows you to take a series of images at a periodic interval and log the images to disk This can be invaluable for monitoring purposes such as asteroid searches or stellar magnitude measurements You can even take
47. ddition to the software provided with the camera there are a number of commercial programs available that will process and enhance electronic images Images may be made to look sharper smoother darker lighter etc Brightness contrast size and many other aspects of the image may be adjusted in real time while viewing the results on the computer screen Two images may be inverted and electronically blinked to compare for differences such as a new supernova or a collection of images can be made into a large mosaic Advanced techniques such as maximum entropy processing will bring out otherwise hidden detail Of course once the image is stored on a computer disk it may be transferred to another computer just like any other data file You can copy it or send it via modem to a friend upload it to your favorite bulletin board or online service or store it away for processing and analysis at some later date We have found that an easy way to obtain a hard copy of your electronic image is to photograph it directly from the computer screen You may also send your image on a floppy disk to a photo lab that has digital photo processing equipment for a professional print of your file Make sure the lab can handle the file format you will send them Printing the image ona printer connected to your computer is also possible depending on your software printer configuration There are a number of software programs available which will print from your scre
48. der to select it it will turn blue as shown below then click OK Browse For Folder Select the Folder that contains drivers For your hardware d Real B RoboHelp Office E E 5 SBIG O ccpopss 3 CcDOpssD 3 CCDOps Spect I Driver Checker SBIG Drivers gt Alt Drivers SereneScreen To view any subfolders click a plus sign above You ll then be back in the Found New Hardware Wizard Click the Next button Found Hew Hardware Wizard Please choose your search and installation options Search for the best driver in these locations Use the check boxes below to limit or expand the default search which includes local paths and removable media The best diver found will be installed Search removable media floppy CD ROM Include this location in the search C Program Files SBIG4Driver Checker SBIG Drivers Browse Don t search will choose the driver to install Choose this option to select the device diver trom a list Windows does not guarantee that the driver you choose will be the best match for pour hardware Page 8 Section 1 Introduction Windows will show the dialog below while it is copying the driver Found New Hardware Wizard Please wait while the wizard installs the software a SBIG USB Loader You may be presented with the dialog below warning you the SBIG USB Loader driver has not passed the Windows Logo testing procedure At t
49. e Figure A1 CCD Connector for TIC Mating Telescope electronic designs are changing rapidly You should check with the manufacturer of your telescope for the actual pinouts of your particular model If this TIC cable does not match your drive port then you can use the information in Table A1 to make a cable to work with your specific telescope drive system Page 70 Appendix B Maintenance B Appendix B Maintenance This appendix describes the maintenance items you should know about with your CCD camera system B 1 Cleaning the CCD and the Window The design of SBIG cameras allows for cleaning of the CCD The optical heads are not evacuated and are quite easy to open and clean When opening the CCD chamber one should be very careful not to damage the structures contained inside To open the CCD Chamber remove the six screws that hold the 5 inch front cover in place Remove the six screws and lift the front cover exposing the structures inside There is a rubber O Ring that sets in the groove on the top of the Chamber housing The CCD array is protected by a thin cover glass that can be cleaned with Q Tips and Isopropyl Alcohol Do not get alcohol on the shutter Dust on the CCD should be blown off Use alcohol only if necessary The optical window of the chamber housing can be cleaned the same way When reinstalling the chamber housing be very careful to make sure the O ring is in the eroove when seated B 2 Regenerating the
50. e Track and Accumulate command Flat field correcting images allow the user to remove the effects of CCD response non uniformity typically less than a few percent and optical vignetting which for some optical systems can be as much as a 50 effect from center to edge The CCDOPS software allows flat field correcting images using the Flat Field command but some preparation must be made to use that command with Track and Accumulate images Essentially you must prepare a special flat field correction image for Track and Accumulate images This special preparation is necessary to have the same set of alignment and co addition operations apply to the flat field file that have occurred in acquiring the Track and Accumulate image In general the following procedure should be followed when flat field correction of Track and Accumulate images is desired 1 Take anormal flat field image using the Grab command You can use the dusk sky or a neutral gray or white card held in front of the telescope Try to adjust the illumination and or exposure so that the build up of light in the image yields values that when co added several times will not overflow 65 000 counts The number of times the image will need to be co added without overflowing is set by how many snapshots you intend to use in Track and Accumulate A good goal is to try and attain a maximum level in the flat field image of 1 000 to 2 000 counts which will allow co addition 32 times without overflow
51. e only difference between this and the previous modification is that two fixed resistors per axis are used to simulate the potentiometer at its mid position You do not need to make modifications to the joystick you essentially build an unadjustable version This may be easier than modifying your hand controller if you can trace out the wiring of your joystick to its connector potentiometer R 2 R 2 A Unmodified Joystick B Joystick Eliminator Figure 4 4 Joystick Eliminator 4 5 Modular Family of CCD Cameras With the introduction of the ST 6 CCD Camera in 1992 SBIG started a line of high quality low noise modular CCD cameras The ST 7E ST 8E and ST 9E were a second family of modular CCD cameras The ST 10E allowed for upgrades to a faster USB interface and larger tracking CCD The benefits of a modular line of CCD Cameras are many fold Users can buy as much CCD Camera as they need or can afford with the assurance that they can upgrade to higher performance systems in the future With a modular approach camera control software like CCDOPS can easily support all models This last point assures a wide variety of third party Page 46 Section 4 Camera Hardware software Software developers can produce one package for the many users across the model line instead of different packages for each of the cameras While the SBIG cameras have many similarities there are also important differences between the products Table 4 2 belo
52. ed sampling 30 Double Correlated Sampling def 67 drive corrector 42 electromechanical shutter 49 electromechanical vane 49 electronic images 33 electronic shutter 49 Establish COM Link Command 38 eyepiece 40 eyepiece holder 37 eyepiece projection 62 eyepiece tube 39 False Color def 67 field of view 31 50 51 52 59 film 25 31 film grain 31 filter wheel 34 filters 34 41 43 62 finding objects 40 fine focus 39 FITS format def 67 flat field 30 41 56 57 Flat Field def 68 flip 41 focal length 52 focal reducer 62 Focal Reducer def 68 focus Dim mode 40 41 fine 39 Full frame mode 39 Full Frame mode 41 peak 39 Planet mode 39 41 68 Focus Command 39 41 focus mode 39 41 Focusing 38 Frame Transfer CCDs 26 Frame Transfer CCDs def 68 frost 28 Full Frame CCDs 26 full well capacity 51 Full Well Capacity def 68 Grab Command 40 41 55 eraphics 40 guiding 32 guiding error 42 59 hand controller 40 42 45 46 hermetic chamber 28 Histogram def 68 host computer 29 37 45 hot pixels 41 IBM PC 29 image processing 29 33 41 63 interference ii IR blocking filter 44 joystick 47 joystick modification 48 library of dark frames 40 56 light frame 30 37 40 light frame def 68 Link 38 LPT port 37 38 45 magnitude diffuse 41 stellar 41 maintenance 73 74 microcontroller 29 modifying hand controller 46 moon 39 52 55 negative image 4
53. eled I2C AUX I squared C and is for future accessories Be sure to keep the static safe cap over this port to insure that you do not accidentally plug in an accessory that is intended for the AO7 CFW8 SCOPE port Plugging in the wrong accessory to the I2C port could cause damage POWER USB I20 AUX AO CFW8 SCOPE C ofce o ofccc2 o More than one accessory can be connected to the accessory ports by using multiple plug adapters provided with the accessory 4 7 Battery Operation The ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM can be operated off of a 12 volt car or marine battery using a the optional 12V power supply or using a power inverter We have used the Radio Shack model 22 132A 12 volt DC to 115 volt AC Portable Power Inverter 140 watt with good success The camera draws 2 2 amps from the battery with this inverter which should enable an evening s operation from a single battery If your camera has the older two stage cooling booster it will when connected draw another 2 amps We recommend a separate battery for the camera using your vehicle s battery with the engine running may add undesirable readout noise and using your vehicle s battery without the engine running may result in a long walk home in the dark Page 51 Section 5 Advanced Imaging Techniques 5 Advanced Imaging Techniques With practice you will certainly develop methods of your own to get the most from your CCD camera In this sect
54. en However we have found that without specialized and expensive equipment printing images on a dot matrix or laser printer yields less than satisfactory detail However if the purpose is simply to make a record or catalog the image file for easy identification a dot matrix or laser printer should be fine Inkjet printers are getting very good though 2 6 Black and White vs Color The first and most obvious appearance of a CCD image is that it is produced in shades of gray rather than color The CCD chip used in SBIG cameras itself does not discriminate color and the pixel values that the electronics read out to a digital file are only numbers proportional to the Page 33 Section 2 Introduction to CCD Cameras number of electrons produced when photons of any wavelength happen to strike its sensitive layers Of course there are color video cameras and a number of novel techniques have been developed to make the CCD chip see color The most common way implemented on commercial cameras is to partition the pixels into groups of three one pixel in each triplet seeing only red green or blue light The results can be displayed in color The overall image will suffer a reduction in resolution on account of the process A newer and more complicated approach in video cameras has been to place three CCD chips in the camera and split the incoming light into three beams The images from each of the three chips in red green and blue light is c
55. ent for each step of the Calibrate Track command 3 Check for flexure between the CCD camera head and your system Check for flexure between the guide scope or off axis guider and your telescope system This is a very common source of guiding errors A very small movement of the CCD head with respect to the guide scope during an exposure can cause unacceptable streaking 4 If your mount is stable try longer exposure times while tracking to average out the atmospheric effects Finding Objects The size of the CCD used in the ST 7 roughly 8mm diagonal can make finding objects a little difficult If you experience this problem you might try the Page 63 Section 8 Glossary following suggestions The easiest method of finding objects is to use a reticule eyepiece if the object is bright enough to see Pull the CCD optical head from the eyepiece holder and insert a 12 20mm eyepiece focusing the eyepiece by sliding it in and out of the eyepiece holder not by adjusting the telescope s focus mechanism Center the object carefully to within 10 of the total field and then replace the CCD optical head Since the head was fully seated against the eyepiece holder when you started fully seating it upon replacement will assure the same focus If the object is too dim to see visually you will have to rely on your setting circles Go to a nearby star or object that is easily visible and center that object in the CCD image Calibrate your RA set
56. ess images The host software and the CCD camera control the telescope through the 9 pin Telescope port on the camera This port provides active low open collector signals to the outside world By interfacing the camera to the telescope s controller the CPU is able to move the telescope as you would by effectively closing one of the four switches that slews the telescope Note You only need to interface the camera s Telescope port to your telescope if you are planning on using the camera system as an autoguider or selfguider or feel you need to have the Track and Accumulate command make telescope corrections between images because your drive has a large amount of long term drift Some recent model telescopes like the Celestron Ultima and the Meade LX200 have connectors on the drive controller that interface directly to the camera s TTL level Telescope port All that s required is a simple cable to attach the 9 pin Telescope port to the telescope s telephone jack type CCD connector SBIG includes its TIC 78 Tracking Interface Cable Adapter for this express purpose although it is easy to modify a standard 6 pin telephone cable for interface to the Telescope port see Appendix A for specific pin outs etc The TIC 78 plugs into the 9 pin port on the ST 7XE ST 8XE ST 9XE ST 10XE ST 10OXME and ST 2000XM and a standard phone cable which we supply connects the adapter to the telescope drive Note phone cables come in a few variations We use t
57. est images during the day Page 22 Section 1 Introduction Camera lens daytime exposure guidelines e Close the F stop all the way to F 16 or F 22 e Set the focus based upon the object and the markings on the lens e Take a short lt 1 second exposure with the Grab command e Display the image e Process the image Page 23 Section 2 Introduction to CCD Cameras 2 Introduction to CCD Cameras This section introduces new users to CCD Charge Coupled Device cameras and their capabilities and to the field of CCD Astronomy and Electronic Imaging 2 1 Cameras in General The CCD is very good at the most difficult astronomical imaging problem imaging small faint objects For such scenes long film exposures are typically required The CCD based system has several advantages over film greater speed quantitative accuracy ability to increase contrast and subtract sky background with a few keystrokes the ability to co add multiple images without tedious dark room operations wider spectral range and instant examination of the images at the telescope for quality Film has the advantages of a much larger format color and independence of the wall plug the SBIG family of cameras can be battery operated in conjunction with a laptop computer though using a power inverter After some use you will find that film is best for producing sensational large area color pictures and the CCD is best for planets faint objects and general
58. f the camera control functions of CCDOPS However because we use CCDOPS solely to develop and test our cameras we are able to post more frequent updates for CCDOPS at our web site for free download You can use either program to control the camera but we suggest starting with CCDOPS to install the USB drivers and to make sure everything is working properly and then move to CCDSoftV5 when you are more familiar with the operations of the camera Follow the instructions below to install and run the CCDOPS software and display and process sample images found at our web site Please follow these directions INSEQUENCE Do not connect the camera to the PC or turn it on until instructed to do so below USB drivers can be difficult to install if you don t follow the instructions Page 4 Section 1 Introduction 1 2 1 Installing the CCDOps and the Driver Checker The first thing you should do in all cases is to install CCDOps version 5 and the Driver Checker utility This is relatively simple 1 2 Make sure the camera is not connected to the computer You will do this later Run the CCDOps Installer It can be found in the CCDOps directory of the CD ROM that came with your camera Follow the onscreen instructions to complete the installation First make sure you are the Administrator or have Administrator privileges if you re running under Windows 2000 or Windows XP On Windows XP Home edition you are the administrator so you don t have t
59. following optional search locations that you specify To start the search click Nest IF you are searching on a floppy disk or CD ROM drive Insert the floppy disk or CD before clicking Hest Optional search locations Floppy disk drives CO ROM drives IY Specify a location Microsoft Windows Update RAR ETETIC DUDS COCO USE HOUSE nS aaa E a e DOSS a aaea a E Back Cancel then click the Next button Page 19 Section 1 Introduction 5 As shown below click the Browse button then navigate to the My Computer C Program Files SBIG Driver Checker SBIG Drivers directory Expand each section by clicking on the next to the name For example scroll to the top and click the next to My Computer then click the next to C etc Click on the SBIG Drivers folder to highlight it then Click OK in the Find File dialog then click OK back at the New Hardware Wizard Found New Hardware Wizard x Inzert the manufacturer s installation disk into the drive ok selected and then click OF Cancel Copy manufacturer s files from C Program Files SBIGS Onver Checker SBG Dry 6 Windows will find the driver and present you with the dialog below Found New Hardware Wizard Driver Files Search Results Pha tae The wizard has finished searching for driver files for Your hardware device SS The wizard found a driver for the following device yi USB Device Windows found a dri
60. follows Camera TC 211 Tracking CCD TC 237 Tracking CCD ST 5C ST 237 237A STV ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME ST 1001E ST 2000XM Pixel Size microns 13 75 x 16 7AX 74 10 x 10 74AX7A 14 8 x 14 8 2x9 20 x 20 6 8 x 6 8 24 x 24 7AX7A Planet Mode Planet Mode is the most useful way to achieve focus When you select Planet mode a full frame is exposed downloaded and displayed on the computer monitor A small window can be placed anywhere in the image area and the size of the window can be changed Subsequent downloads will be of the area inside the box resulting in a much faster update rate Quantum Efficiency Quantum Efficiency refers to the fractional number of electrons formed in the CCD pixel for a given number of photons Quantum Efficiency is usually plotted as a function of wavelength Page 66 Section 8 Glossary Readout Noise Readout noise is associated with errors generated by the actual interrogation and readout of each of the CCD pixels at the end of an exposure This is the result of fixed pattern noise in the CCD residual charge in the readout capacitors and to a small extent the noise from the A D converter and preamplifier Resolution Mode The resolution of a CCD camera is determined by pixel size Pixel size can be increased by combining or binning more than one pixel and displaying it as one pixel Doing so decreases the effective resolution but speeds up the download time of the
61. from the telescope Note that there are electronics inside the chassis that can be damaged by long bolts Make sure nothing threaded into the tripod hole is longer than 0 200 5mm When possible we also recommend using the T Ring attachments for connecting the camera to the telescope as the cameras are heavy Page 35 Section 3 At the Telescope with a CCD Camera et RA POWER USB 12C AUX AO7 CFW8 SCOPE C ofen o ofccce o Figure 3 1 Orientation of the Optical Head Viewed from Back Pixel 1 1 is at the upper left in this view 3 3 Establishing a Communications Link After setting up the software and the camera as described in the previous sections using CCDOPS software establish a link to the camera by clicking on the Establish Comm Link command from the Camera menu If the software is successful the Link field in the Status Window is updated to show the type of camera found If the camera is not connected powered up or the USB port has not yet been properly selected a message will be displayed indicating that the software failed to establish a link to the camera If this happens use the Communications Setup command in the Misc menu to configure the CCDOPS software for the USB Then use the Establish COM Link command in the Camera Menu to establish communications with the camera Note Itis not necessary to have a camera connected to your computer to run the software and display images already saved onto
62. ft not to slew the telescope 2 The Resolution setting in the Camera Setup command combines pixels before they are digitized This is referred to as on chip binning and offers increases in frame digitization rates Page 40 Section 3 At the Telescope with a CCD Camera One of the reasons that SBIG autoguiders are often better than human guiders is that rather than just stabbing the hand controller to bump the guide star back to the reticule it gives a precise correction that is the duration necessary to move the guide star right back to its intended position It knows how much correction is necessary for a given guiding error through the Calibrate Track command The Calibrate Track command which is used prior to autoguiding exercises the telescope s drive corrector in each of the four directions measuring the displacement of a calibration star after each move Knowing the displacement and the duration of each calibration move calibrates the drive s correction speed Once that is known the CCD tracker gives the drive corrector precise inputs to correct for any guiding error When self guiding is selected by invoking the Self Guiding command under the Track Menu the computer prompts the user for the exposure time for the tracking and imaging CCDs Once these are entered the computer takes and displays an image with the tracking CCD and the user selects a guide star using the mouse Guide stars that are bright but not saturating and isolate
63. he image This very reason is why deep sky filters are so popular with astrophotography They reduce the sky background level increasing the contrast of dim objects They will improve CCD images from very light polluted sights Page 29 Section 2 Introduction to CCD Cameras 2 4 2 Double Correlated Sampling Readout During readout the charge stored in a pixel is stored temporarily on a capacitor This capacitor converts the optically generated charge to a voltage level for the output amplifier to sense When the readout process for the previous pixel is completed the capacitor is drained and the next charge shifted read and so on However each time the capacitor is drained some residual charge remains This residual charge is actually the dominant noise source in CCD readout electronics This residual charge may be measured before the next charge is shifted in and the actual difference calculated This is called double correlated sampling It produces more accurate data at the expense of slightly longer read out times two measurements are made instead of one The ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM utilize double correlated sampling to produce the lowest possible readout noise At 10e to 15e rms per read these cameras are unsurpassed in performance 2 4 3 Dark Frames No matter how much care is taken to reduce all sources of unwanted noise some will remain Fortunately however due to the nature of electron
64. he six pin cable and the pin order is reversed left to right relative to the connector from one end to the other This is identical to what is typically sold at Radio Shack stores as an extension cable 4 4 1 Using Mechanical Relays Older telescopes generally require modifying the hand controller to accept input from the camera s Telescope port The difficulty of this task varies with the drive corrector model and may require adding external relays if your drive corrector will not accept TTL level signals We maintain a database of instructions for the more popular telescopes that we will gladly share with you For a minimal charge will also modify your hand controllers if you feel you do not have the skills necessary to accomplish such a task We sell a mechanical relay box that interfaces to the ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM and will interface to the older drives Contact SBIG for more information In general the camera has four signals that are used in tracking applications There is one output line for each of the four correction directions on the hand controller North South East and West Our previous cameras had internal relays for the telescope interface but with the proliferation of TTL input telescopes the relays were removed We do offer an external relay adapter accessory The following paragraphs describe the general purpose interface to the telescope which involves using external relays Page 44 Secti
65. he telescope Electromechanical Shutter Having the shutter in the ST 7E 8E 9E 10E 1001E gives streak free readout and allows taking dark frames without having to cover the telescope While the minimum exposure is 0 11 seconds repeatability and area uniformity are excellent with SBIG s unique unidirectional shutter Shutter Wheel The Shutter Wheel used in conjunction with the camera s Electronic shutter allows you to cover the CCD for taking dark frames and in the case of the ST 5C 237 237A allows replacement with a mini internal color filter wheel Electronic Shutter Having an electronic shutter involves having a CCD with a frame transfer region These CCDs actually have an array that has twice the number of rows advertised where the bottom half is open to the light referred to as the Image Area and the top half is covered with a metalization layer referred to as the Storage Area In frame transfer CCDs at the end of the exposure the pixel data from the Image Area is transferred into the Storage Area very rapidly where it can be read out with a minimum of streaking Page 47 Section 4 Camera Hardware In addition to the system level differences between the various cameras Table 4 3 below quantifies the differences between different CCDs used in the cameras Camera TC211 Tracking CCD TC237 Tracking CCD ST S5C ST 237A STV ST 7XE ST 8XE ST 9XE ST 10XE XME ST 1001E ST 2000XM How these various specifications
66. hen present you with the Found New Hardware Wizard shown below Click the Next button Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard helps you install a device driver for a hardware device To continue click Mest Cancel Page 18 Section 1 Introduction 3 Click the Search for suitable driver radio button as shown below Found New Hardware Wizard Install Hardware Device Drivers ha Bae A device driver it a software program that enables a hardware device to work with Sy an operating system This wizard will complete the installation for this device 7l USE Device A device driwer iz a software program that makes a hardware device work Windows needs driver files for your new device To locate driver files and complete the Installation click Nest what do you want the wizard to do Search for a suitable driver for my device recommended Display a list of the known drivers for this device so that can choose a specific driver Back Cancel then click the Next button 4 Uncheck all the options other than Specify a location as shown below Found New Hardware Wizard p Locate Driver Files Pha tae Where do you want Windows to search for driver files Ss Search for driver files for the following hardware device 72 USB Device The wizard searches for suitable drivers in its driver database on your computer and in any of the
67. his machine and run it B Whether you have an internet connection or not then click the Update button This will copy the current drivers to your system and make sure they are properly installed Some new computers without parallel ports will report that the SBIGUDRV SYS was not started Don t worry about that The SBIGUDRV SYS S is the parallel port camera driver and is not use with USB cameras You may be asked to reboot your system as well If so click Done and do so Otherwise simply click Done 6 Follow the instruction in Sections 1 2 2 1 1 2 2 2 or 1 2 2 3 below depending on the version of Windows you have on your computer 1 2 2 1 Add New Hardware Wizard for Windows XP Users 1 With the camera disconnected from the computer plug in the power to the camera and if your power supply has a power switch turn on the power to the camera 2 Plug the camera into the computer with the supplied USB cable The computer will then present you with the Found New Hardware Wizard Click the Install from a list radio button then click the Next button Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard helps you install software for USB Device fe If your hardware came with an installation CD ae mi or floppy disk insert it now what do you want the wizard to do Install the software automatically Recommended Click Next to continue Page 6 3 Section 1 I
68. his point click the Continue Anyway button Hardware Installation The software you are installing for this hardware SBlG USE Loader has not passed Windows Logo testing to venty its compatibility with Windows AP Tellme why this testing is important Continuing your installation of this software may impair or destabilize the correct operation of your system either immediately or in the future Microsoft strongly recommends that you stop this installation now and contact the hardware vendor for software that has passed Windows Logo testing Continue Anyway Page 9 Section 1 Introduction 6 Windows will continue installing the driver as shown in the dialog below Found New Hardware Wizard Please wait while the wizard installs the software SBlG USB Loader sbiguebe rit To CAWINDOW S INF Completing the Found New Hardware Wizard The wizard has finished installing the software for SBIG USB Loader Click Finish to close the wizard Finish Hit the Finish button At this point the Camera s Fan and LED should come on You are half way through the installation of the drivers Page 10 Section 1 Introduction 8 Again you will be presented with the Found New Hardware wizard for the SBIG USB Camera driver as shown in the dialog below Repeat steps 3 through 7 for this driver just like you did before Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard he
69. hree color band filters Second since you have narrowed the CCD s wavelength response with the interference filters longer exposures are required to achieve a similar signal to noise compared to what one would get in a monochrome image with wide spectral response This is added to the fact that tri color images require a higher signal to noise overall to produce pleasing images With black and white images your eye is capable of pulling large area detail out of random noise quite well whereas with color images your eye seems to get distracted by the color variations in the noisy areas of the image The moral of the story is that while you can achieve stunning results with CCD color images it is quite a bit more work Page 42 Section 4 Camera Hardware 4 Camera Hardware This section describes the modular components that make up the CCD Camera System and how they fit into the observatory with all their connections to power and other equipment 4 1 System Components The ST 7XE ST 8XE ST 9XE ST 10XE ST 1OXME and ST 2000XM CCD cameras consist of four major components the CCD Sensors and Preamplifier the Readout Clocking Electronics the Microcontroller and the power supply All the electronics are packaged in the optical head in these cameras with an external desktop power supply The CCDs Preamplifier and Readout Electronics are mounted in the front of the optical head The optical head interfaces to the telescope through a 1 25
70. ic imaging and the use of computers for storing and manipulating data this remaining noise can be drastically reduced by the subtraction of a dark frame from the raw light image A dark frame is simply an image taken at the same temperature and for the same duration as the light frame with the source of light to the CCD blocked so that you get a picture of the dark This dark frame will contain an image of the noise caused by dark current thermal noise and other fixed pattern noise such as read out noise When the dark frame is subtracted from the light frame this pattern noise is removed from the resulting image The improvement is dramatic for exposures of more than a minute eliminating the many hot pixels one often sees across the image which are simply pixels with higher dark current than average 2 4 4 Flat Field Images Another way to compensate for certain unwanted optical effects is to take a flat field image and use it to correct for variations in pixel response uniformity across the area of your dark subtracted image You take a flat field image of a spatially uniform source and use the measured variations in the flat field image to correct for the same unwanted variations in your images The Flat Field command allows you to correct for the effects of vignetting and nonuniform pixel responsivity across the CCD array The Flat Field command is very useful for removing the effects of vignetting that may occur when using a field comp
71. ies 63 adaptive optics 62 antiblooming 51 67 Antiblooming Gate def 67 AO 7 62 astrometric measurements 67 Astrometry def 67 astrophotography 33 atmospheric effects 39 auto contrast 40 Auto Grab Command 43 autoguider 29 42 45 58 67 Autoguider def 67 background parameter 40 battery operation 37 45 binning 31 Calibrate Track Command 43 59 calibration star 59 camera lens adapter 55 62 Camera Setup Commands 42 CCD 28 32 def 67 cameras 25 26 29 37 45 48 49 50 cleaning 73 74 detector 25 27 45 orientation 37 CCDCOLOR software 44 CCDOPS software 29 centering objects 40 cleaning the CCD 73 74 clock drivers 28 co add images 25 42 45 cold pixels 41 color filter wheel 43 62 color images 34 43 color table 67 commands Auto Grab 43 Calibrate Track 43 59 Dark Subtract 41 Focus 39 41 Grab 40 41 55 Track 59 Track and Accumulate 42 55 59 Tracking Parameters 59 Commands Index 77 Establish COM Link 38 PC Setup 38 communications link 38 connector Telescope 71 72 connector CPU RELAYS 45 59 cooling 29 70 co register images 42 45 crop 40 crosshairs 40 dark current 29 dark frame 28 30 37 40 41 Dark Frame def 67 Dark Noise def 67 Dark Subtract Command 41 dark subtracted 30 37 41 DCS 30 67 Declination 37 45 59 66 desiccant 73 Diffuse Magnitude 41 diffuser 38 Dim mode 41 displaying images 40 double correlat
72. ion we offer some suggestions to save you time getting started in each of the different areas outlined below but these suggestions are by no means exhaustive 5 1 Lunar and Planetary Imaging When imaging the moon using most focal lengths available in astronomical telescopes you will note that the moon s image typically fills the CCD The image is also very bright The best way to image the moon is to use neutral density filters to attenuate the light You may also try an aperture mask to reduce the incoming light If you feel that an aperture mask reduces resolution to an unacceptable degree consider using a full aperture solar filter This will result in an optimum exposure of only a few seconds Another way to reduce the incoming light is to increase the effective focal length of your telescope by using a barlow lens or eyepiece projection This is very desirable for planetary imaging since it also increases the image size 5 2 Deep Sky Imaging Ordinarily with telescopes of 8 aperture or larger a ten second exposure in focus mode with a dark frame subtracted will show most common deep sky objects except for the very faintest This is a good starting point for finding and centering deep sky objects If you find ten seconds to be insufficient a one minute exposure will clearly show nearly any object you wish to image particularly if 2x2 or 3x3 binning is selected Using the Grab command exposures of five minutes will generally give you
73. ixels themselves really plays into the user s selection of the system focal length Smaller pixels and smaller CCDs require shorter focal length telescopes to give the same field of view that larger CCDs have with longer focal length telescopes Smaller pixels can give images with higher spatial resolution up to a point When the pixel dimensions in arcseconds of field of view get smaller than roughly half the seeing decreasing the pixel size is essentially throwing away resolution Another aspect of small pixels is that they have smaller full well capacities For your reference if you want to determine the field of view for a pixel or entire CCD sensor you can use the following formula Field of view arcseconds Field of view arcseconds 8 12x size um focal length inches 20 6x size um focal length cm 3 The Kodak CCDs KAF0400 and KAF1600 are available with or without Antiblooming Protection Units with the Antiblooming Protection have one half the full well capacity of the units without it Page 48 Section 4 Camera Hardware where size is the pixel dimension or CCD dimension in millimeters and the focal length is the focal length of the telescope or lens Also remember that 1 3600 arcseconds Read Noise The readout noise of a CCD camera affects the graininess of short exposure images For example a CCD camera with a readout noise of 30 electrons will give images of objects producing 100 photoelectrons
74. lation to further increase the cooling capability of the camera Without flowing water the cooling improvement is about 6 degrees C With it the cooling improvement is about 15 degrees C If you plan to use it without the water then you should disconnect the hoses from the camera and shake out the water trapped in the heat sink Disconnecting the hoses will reduce the potential perturbation to your telescope mount To operate the cooling booster without water cooling mount the camera to the telescope as before and simply plug the auxiliary 12 volt supply jack into the connection on the camera back plate Turn on the TE cooling to 100 by giving it a target temperature of 50 degrees After 10 minutes examine the camera temperature and reset the set point to 3 degrees C above Page 73 Appendix D Use and Maintenance of the Cooling Booster the current temperature This 3 degree temperature margin will enable the ST 7 8 to regulate the temperature accurately To operate the camera with water cooling the procedure is the same except that the water flow must be established before mounting the camera to the telescope since the water pumps have limited pressure capability To do this put the camera at the same level as the water reservoir Connect all the hoses and make sure the water return goes back into the reservoir Push the inch internal diameter ID hoses onto the nipples on the back of the camera so they seal Attach one hose to the ni
75. llows you to mount your camera lens in place of the telescope for very wide field views of the night sky or for daytime terrestrial imaging The adapters are available for a variety of the most common camera lenses in use The cameras themselves can be used for eyepiece projection assuming you already have a T thread eyepiece projection adapter for Instead of attaching a 35mm camera to the T thread camera adapter you can attach the CCD camera by unscrewing the T Thread nosepiece fom the front of the camera 6 4 Focal Reducers Several third party vendors including Optec Celestron and Meade make focal reducers for their telescopes that could be used with the ST 7XE 8XE 9XE 10XE ST 1OXME and ST 2000XM cameras While most will work with the ST 7XT some may have slight amounts of vignetting when used on the larger 8XE 9XE 10XE ST 1OXME and ST 2000XM Note Many very fast F 3 3 commercial units will not accommodate a filter wheel 6 5 AO 7 and Lucy Richardson Software The AO 7 is the world s only Adaptive Optics accessory for the amateur CCD market and it works only with the self guided feature of the ST 7XE 8XE 9XE 10XE ST 1OXME and ST 2000XM The AO 7 is essentially an electromechanical driven diagonal mirror that goes between the camera and the telescope Using the AO 7 allows corrections to be made at rates up to 40 Hz This yields perfect backlash free guiding and allows removal of some atmospheric effects When used in conjun
76. losity and is due to city lights and sky glow High levels of sky background can increase the noise in images just like dark current For some objects deep sky filters can be used to reduce the sky background level The e Count shown are for the High Resolution readout mode These numbers can be different for other readout modes Use the Parameters command in the Display menu to see the actual value for images acquired in other readout modes 9 The non ABG versions of the ST 7E 8E have twice the full well capacity of the values shown ABG version may also vary from camera to camera with maximum counts being as high as 30 000 Page 67 Section 8 Glossary Seeing Seeing refers to the steadiness and the clarity of the atmosphere during an observing session TE Cooler The TE Cooler is a Thermal Electric cooling device used to cool the CCD down to operating temperature The CCD is mounted to the TE Cooler which is mounted to a heat sink usually the camera head housing TIFF Image File Format The TIFF image file format which stands for Tagged Interchange File Format was developed jointly by Microsoft and Aldus Corporations to allow easy interchange of graphics images between programs in areas such as presentation and desktop publishing CCDOPS can save image files in this format but it can not read them Track and Accumulate The Track and Accumulate function is a SBIG patented feature of CCDOPS that allows the user to automatically c
77. lps you install software for SBIG USB Camera If your hardware came with an installation CD lt o floppy disk insert it now What do pou want the wizard to do O Install the software automatically Recommended Click Next to continue 9 At one point you may be presented with the following dialog Found Hew Hardware Wizard Please select the best match for your hardware from the list below a SBIG USB Camera Description SBIGUSB Camera 20 00 SBIG c windows infksbiguebe int SBIG USB Camera 20 0 0 SBIG cMindows in hoem 0 ink This driver is not digitally signed Tell me why diver signing is important lt Back Next gt Cancel Select the top entry and hit the Next button When you re all done if you open the System Control Panel from the Start Menu select the Hardware tab then click the Device Manager button and finally expand the Universal Serial Bus Controllers section at the bottom you should see the SBIG USB Camera entry as shown below Page 11 Section 1 Introduction Device Manager CEE File Action View Help 4 amp Warts och i Computer See Disk drives a Display adapters A DYDICD ROM drives Floppy disk controllers dh Floppy disk drives IDE ATALATAPI controllers gt Keyboards Mice and other pointing devices Monitors B Network adapters YF Ports COM amp LPT ie Processors Sound video and game controllers System devices
78. mage you wish to correct The software will load the TRACK file and present you with another file directory dialog showing all the images Select the appropriate FLAT image The software will align and co add the FLAT image using the same operations it performed on the Track and Accumulate image Finally save the combined flat field image using the Save command In the following discussions this combined flat field image will be referred to as COMBINED FLAT Repeat this step for each of the TRACK files using a corresponding name for the COMBINED FLAT image 7 You will now flat field correct the Track and Accumulate image with the combined flat field image Use the Open command to load the IMAGE file then use the Flat Field command The software will present you with a file directory dialog where you should select the corresponding COMBINED FLAT image After the software has finished correcting the image you can view the results and save the flat field corrected image with the Save command This image will be referred to as the CORRECTED IMAGE file Repeat this step for each of the IMAGE files using the corresponding COMBINED FLAT image At SBIG we have adopted the following naming convention for our various image and related files If it helps you organize your files please feel free to adopt it or any method you feel helps sort out the process of naming files Image type Name Uncorrected image IMAGE XXXXXXXX blank extension Flat field file
79. mera for the first time on a particular computer If you wish to run your SBIG USB camera from more than one computer you must go through the USB driver installation process for each computer you intend to use For users new to the field of CCD Astronomy Sections 2 3 and 4 offer introductory material about CCD Cameras and their applications in Astronomy Users who are familiar with CCD cameras may wish to skip section 2 and browse through sections 3 and 4 reading any new material Thoroughly experienced SBIG customers may wish to jump right to the separate Software Manual which gives detailed and specific information about the SBIG software Sections 5 and 6 offer hints and information about advanced imaging techniques and accessories for CCD imaging that you may wish to read after your initial telescope use of the CCD camera Finally section 7 may be helpful if you experience problems with your camera and the Appendices provide a wealth of technical information about these systems 1 2 Installing the USB Drivers for the First Time If you are installing an SBIG USB camera for the first time use this section to walk you through the driver installation process To operate the camera you must first install camera control software onto your computer or laptop Your camera comes with two programs CCDOPS from SBIG and CCDSoftV5 which was jointly written by Software Bisque and SBIG CCDSoftV5 is a very comprehensive program that incorporates many o
80. mera functions in an integrated package 6 7 2 Image Processing Software There are a host of image processing software packages capable of reading and processing FITS and TIFF files and many packages will read and process native SBIG image formats as well In addition to commercial software a number of web sites offer public domain and shareware programs 6 7 3 Getting Hardcopy One older way of producing a hard copy of images taken with the CCD camera is to simply take a photograph of the computer screen while the image is displayed It is best to use a long lens and step back from the monitor to reduce the appearance of the curvature of the edges of the screen and use an exposure longer than 1 30th of a second to avoid the video refresh rate of your monitor Darken the room and use a brighter background than is visually optimum For the best quality hard copy save the files in TIFF format and send a copy of the file on a disk to a photo lab which offers printing of digital images The Windows version of CCDOPS allows for printing of the images and there are a number of third party software programs for the PC such as Pizzaz Plus which will capture and print the display on your computer screen These programs however do not produce very detailed prints and are useful only to a very limited degree Recently photo quality color desktop printers have become commonplace Many of these printers will do a reasonable job with commercial image p
81. mm 145 inches 23000mm 900 inches 1040mm 41 inches 1040mm 41 inches 1 3 x 1 arcminutes 6400mm 250 inches Table 4 5 Focal Length Required M51 Whirlpool Galaxy M27 Dumbell Nebula M57 Ring Nebula 8x5 arcminutes 8 5 x 5 5 arcminutes From these numbers you can deduce that the popular C8 an 8 10 telescope will nicely frame many popular objects with the ST 7XE whereas a much shorter system f 3 perhaps achieved with a focal reducer will frame the same objects for the tracking CCD Another point to bear in mind is that except for planetary images you ll rarely take images where the pixel size in seconds of arc is down near the seeing limit Most objects are relatively large where the field of view is more important than whether the individual pixels are less than half the seeing 4 6 Connecting accessories to the Camera There are two 9 pin accessory ports on the ST X series of cameras The first is labeled AO7 CFW8 SCOPE This is the port that supports our AO 7 Adaptive optics device CFW8A color 4 6 3 telescope with an f 6 3 focal reducer and star diagonal Page 50 Section 4 Camera Hardware filter wheel and relay adapter box It is also the relay output for direct connection to many popular telescopes CCD autoguiding port Note This is not the same thing as the telescope s RS232 port that is commonly used to point and slew the telescope The second accessory port on the camera is lab
82. ne lies for your telescope you can use Table 3 1 to calculate exactly where the CCD is with respect to your system By placing the CCD close to the focal plane initially you can save a lot of time The best kind of object to focus on is a star As you converge towards focus more light from the star will be concentrated onto one pixel Thus watching your peak reading while focusing and focusing for a maximum reading is a good way to get best focus This is how we do it It helps to have a dial or indicator on the focus knob so you can rapidly return to the best point after going through focus Elongated Guided Images When using Track and Accumulate or Self Guiding if you notice guiding errors resulting in elongated star images you are probably using too long a snapshot time If the snapshot time is longer than the amount of time your drive can track unguided with acceptable guiding errors you will see elongated stars in your final images If your snapshot times are getting down to 30 seconds or less you should improve your drive If you are using your camera as an autoguider for film photography and are noticing unacceptable guiding errors please check the following before calling SBIG 1 Can you move the telescope using the Move command This is an indicator as to whether or not you are properly connected to your drive system via the relay cable from the CPU 2 Be sure that your calibration time gives at least 10 to 50 pixels of movem
83. not necessary then There is no problem using the camera at any time without water circulation Adding water circulation simply improves the cooling performance With water circulation the improvement in cooling is about 10 degrees C better than with air only You may supply your own pump and tubing or use the optional pump and tubing available from SBIG To operate the camera with water circulation using the optional pump available from SBIG start with the camera at the same level as the water reservoir Connect all the hoses and make sure the water return goes back into the reservoir Push the 1 4 inch internal diameter ID hoses onto the nipples on the back of the camera so they seal Attach one hose to the nipple onto the reducing connector that adapts the inch ID hose to the 1 2 inch diameter hose from the pump Turn on the pump and let the flow establish itself through the hoses Next mount the camera to the telescope If you always keep the return hose outlet near the reservoir level the pump will have no problem raising the water 2 meters 6 feet off the floor The limited pressure capacity of the pump is only a problem when you let the water fall back into the reservoir from a significant height above it such a 0 3 meter 12 inches Lastly check for leaks Once you have established water circulation turn on the TE cooler to 100 by giving it a target temperature of 50 degrees Wait for about 10 to 20 minutes for the system to sta
84. ntroduction As shown below click the Search for the best driver radio button then check the Include this location checkbox then click the Browse button Found New Hardware Wizard Please choose your search and installation options Search for the best driver in these locations Use the check bores below to limit or expand the default search which includes local paths and removable media The best driwer found will be installed Search removable media floppy CO ROM Include this location in the search O Dont search will choose the driver to install Choose this option to select the device diver from a list Windows does not guarantee that the driver you choose will be the best match for your hardware You will see the Browse for Folder dialog shown below Browse For Folder Select the folder that contains drivers For your hardware Desktop F3 G My Documents Ez P My Computer H J My Network Places 9 Color Demosaicing To view any subfolders click a plus sign above i Cancel Navigate through the directory structure of you hard drive to the My Computer C Program Files SBIG Driver Checker SBIG Drivers Page 7 Section 1 Introduction directory Expand each section by clicking on the next to the name For example scroll to the top and click the next to My Computer then click the next to C etc Finally click on the SBIG Drivers fol
85. o register and co add including dark frame subtraction a series of images of an object These exposures can be taken unguided as long as the Snapshot time does not exceed the length of time before tracking errors of your clock drive become apparent This allows you to image and track without guiding or the need to connect the CCD Relay port to your drive motors Track List The Track List is an ASCII file generated by CCDOPS during a Track and Accumulate session The Track List logs all the corrections made by CCDOPS for each of the images Track lists are required when flat fielding Track and Accumulate images Tri Color Tri Color refers to color images created using three different colors mixed into a balanced color image using red green and blue filters An object is imaged three times once with each color filter The three images are then co added and color balanced with the appropriate software Vignetting Vignetting is obstruction of the light paths by parts of the instrument It results in an uneven illumination of the image plane The effects of vignetting can be corrected using flat field images Page 68 Appendix A Connector Pinouts A Appendix A Connector and Cables A 1 Connector Pinouts for the AO7 CFW8 SCOPE port Pin Number Function Chassis Ground CFW 8 Pulse AO 7 Data Out Plus X Active Low Open Drain b Plus Y Active Low Open Drain Signal Ground Minus X Active Low Open Drain Minus Y Active
86. o worry about that Next run the Driver Checker Installer It can be found in the Driver Checker folder of the CD ROM Towards the end of the Driver Checker installation the installer will run the utility This utility checks to make sure you have the latest version of the SBIG camera drivers installed on your system When the SBIGDriverChecker utility is run you ll see a dialog like O SBIGDriverChecker D SBIG Driver Checker Utility ee Hit the About Help button for Help Currently Installed Drivers boutr Help Driver Name Version Current 4 35 Build 6 03 10 04 4 06 08 23 02 0 Build 36 11 04 03 shiglldr O0 11 04 03 shigfldr 61 03 12 04 sbiqushe a 09 05 03 stiga bin 8 25 03 08 28 03 If you have previously installed CCDOPS you ll see some entries in the table Most likely one or more drivers is not installed or is not up to date Also if this is the first time you ve run the Driver Checker you may get a warning something like The sbigudrv service can not be found Just ignore this error Page 5 Section 1 Introduction 5 Using the Driver Checker to update your drivers is a two step process A If you have an internet connection Click on the Download button then follow the instructions to download the current drivers from SBIG s Servers If you don t have an internet connection on this machine then make sure you have downloaded the latest Driver Checker Installer from SBIG s web site copied it to t
87. ombined to form a color image Resolution is maintained For normal video modes where there is usually plenty of light and individual exposures are measured in small fractions of a second these techniques work quite well However for astronomical work exposures are usually measured in seconds or minutes Light is usually scarce Sensitivity and resolution are ata premium The most efficient way of imaging under these conditions is to utilize all of the pixels collecting as many photons of any wavelength as much of the time as possible In order to produce color images in astronomy the most common technique is to take three images of the same object using a special set of filters and then recombine the images electronically to produce a color composite or RGB color image SBIG offers as an option an integrated motorized color filter wheel The CFW8A color filter wheel is attached to the front of the camera in such a way that light entering the camera passes through the colored filter before it strikes the CCD An object is then exposed using a red filter The wheel is commanded to insert the green filter in place and another image taken Finally a blue image is taken When all three images have been saved they may be merged into a single color image using SBIG or third party color software Use nosepiece from camera or T thread adapter to attach to telescope Removable nosepiece T threads Motor T threads Cavar CFW 8A Color
88. on 4 Camera Hardware In our older camera models and in the optional relay adapter accessory each of the relays has a Common a Normally Open and a Normally Closed contact For example when the relay is inactivated there is a connection between the Common and the Normally Closed contact When the relay is activated trying to correct the telescope the contact is between the Common and the Normally Open contacts If your hand controller is from a relatively recent model telescope it probably has four buttons that have a push to make configuration By push to make we mean that the switches have two contacts that are shorted together when the button is pressed If that s the case then it is a simple matter of soldering the Common and Normally Open leads of the appropriate relay to the corresponding switch without having to cut any traces as shown in Figure 4 1 below B Modified Push to Make Switch q common 1 FA i switch i E normally open Figure 4 1 Push to Make Switch Modification A Unmodified Push to Make Switch Another less common type of switch configuration although it seems to have been used more often in older hand controllers involve hand controller buttons that use both a push to make contact in conjunction with a push to break contact The modification required for these switches involves cutting traces or wires in the hand controller Essentially the relay s Normally Open is wired in parallel with the swit
89. pple onto the reducing connector which adapts the 1 4 inch ID hose to the 1 2 inch diameter hose from the pump Turn on the pump and let the flow establish itself through the hoses Next mount the camera to the telescope If you always keep the return hose outlet near the reservoir level the pump will have no problem raising the water 2 meters 6 feet off the floor The limited pressure capacity of the pump is only a problem when you let the water fall back into the reservoir from a significant height above it such a 0 3 meter 12 inches Lastly check for leaks When using water cooling avoid the temptation to put ice in the water to get the camera even colder As the cooling booster is designed the camera will not be cooled below ambient temperature if ambient temperature water is used If colder water is used the head may fog or frost up depending on the dew point The exposed electronics inside the ST 7 8 will get wet and corrode The hoses will start dripping condensation and you will have a mess Keep the ice for a cold drink At the end of the evening stop the pump and raise the outlet hose above the camera to let all the water drain out of the system Blowing it out with gently pressure helps clear the water You can leave the hoses full of water but if a leak occurs while you re not there you may have a problem When packing the camera for a long time or at the end of summer disconnect the hoses and blow out the heat sink
90. pply Operation from a car or marine battery is possible using the optional 12V power supply or with a 12V to 110V power inverter Connect the CCD head to the USB port of your computer using the supplied cable and insert the CCD Camera s nosepiece into your telescope s eyepiece holder Fully seat the camera against the end of the draw tube so that once focus has been achieved you can swap out and replace the camera without having to refocus Orient the camera so that the CCD s axes are aligned in Right Ascension and Declination Use Figure 3 1 below showing the back of the optical head as a guide for the preferred orientation Any orientation will work but it is ageravating trying to center objects when the telescope axes don t line up fairly well with the CCD axes Next connect the power cable and plug in the desktop power supply A few seconds after you establish a link using CCDOPS software the red LED on the rear of the camera should glow and the fan should spin indicating that the firmware has been uploaded to the camera and it is ready for operation We recommend draping the cables over the finderscope saddle or mount to minimize cable perturbations of the telescope and guard against the camera falling out of the drawtube to the floor In the alternative there is a 14 20 threaded hole on the side plate of the camera used for tripod mounting This is also a convenient place to attach a safety strap to prevent the camera from accidentally falling
91. re shown in Table 3 2 below Another point you should also be aware of is that as you approach a good focus the peak reading can vary by 30 or so This is due to the fact that as the star image gets small where an appreciable percentage of the light is confined to a single pixel shifting the image a half a pixel reduces the peak brightness as the star s image is split between the two pixels The Kodak CCD pixels are so small that this is not likely to be a problem Table 3 1 Camera Back Focus Resolution Saturation Counts High Res 20 000 for ST 7XE 8XE ABG Cameras 40 000 for ST 7XE 8XE Non ABG cameras 50 000 for ST 1IOXE Camera 65 000 for ST 9XE 2000XM Cameras Med Low Res 65 000 for ST 7 8 9 10 2000 Table 3 2 Saturation Values Page 37 Section 3 At the Telescope with a CCD Camera Once the best focus is found the focusing operation can be greatly shortened the second time by removing the CCD head being careful not to touch the focus knob Insert a high power eyepiece and slide it back and forth to find the best visual focus and then scribe the outside of the eyepiece barrel The next time the CCD is used the eyepiece should be first inserted into the tube to the scribe mark and the telescope visually focused and centered on the object At 6 the depth of focus is only 0 005 inch so focus is critical An adapter may be necessary to allow the eyepiece to be held at the proper focus position SBIG sells extenders for this p
92. ression lens and the fixed pattern responsivity variations present in all CCDs It is often difficult to visually tell the difference between a corrected and uncorrected image if there is little vignetting so you must decide whether to take the time to correct any or all of your dark subtracted images It is always recommended for images that are intended for accurate photometric measurements Appendix D describes how to take a good flat field It s not that easy but we have found a technique that works well for us Page 30 Section 2 Introduction to CCD Cameras 2 4 5 Pixels vs Film Grains Resolution of detail is determined to a certain degree by the size of the pixel in the detector used to gather the image much like the grain size in film The pixel size of the detector in the ST 10XE is 6 8 x 6 8 microns 1 micron 0 001mm 0 04 thousandths of an inch In the ST 7XE and ST 8XE it is 9 x 9 microns in the ST 9XE it s 20 x 20 microns and in the ST 2000XM it is 7 4 x 7 4 microns However the effects of seeing are usually the limiting factor in any good photograph or electronic image On a perfect night with excellent optics an observer might hope to achieve sub arcsecond seeing in short exposures where wind vibration and tracking error are minimal With the average night sky and good optics you will be doing well to achieve stellar images in a long exposure of 3 to 6 arcseconds halfwidth This will still result in an attractive image
93. rge the signal to noise of images like these is proportional to the square root of the total number of electrons To get twice the signal to noise you would have to increase the exposure 4 times An ST 5C with its relatively low full well capacity of 50 000e could produce an image with a S N in excess of 200 Antiblooming Most SBIG CCD cameras have antiblooming protection The TI CCDs used in the ST 5C ST 237 ST 237A TC 237 autoguider and TC 211 autoguider have antiblooming built into the CCDs The Kodak CCDs used in the ST 7XE and ST 8XE have Antiblooming versions of the CCDs available and the CCD used in the ST 2000XM only comes with antiblooming Blooming is a phenomenon that occurs when pixels fill up As charge continues to be generated in a full pixel it has to go somewhere In CCDs without antiblooming protection the charge spills into neighboring pixels causing bright streaks in the image With the CCDs used in the SBIG cameras the excess charge can be drained off saturated pixels by applying clocking to the CCD during integration This protection allows overexposures of 100 fold without blooming The trade off is sensitivity Antiblooming CCDs are less sensitive than non antiblooming CCDs In the case of the ST 7XE and ST 8XE for example the non antiblooming versions are very roughly twice as sensitive The CCDs used in the ST 9XE ST 10XE and ST 10XME and ST 1001E detectors do not come in an antiblooming version Page 49 Se
94. rocessing programs such as Adobe Photoshop 6 8 SBIG Technical Support If you have any unanswered questions about the operation of your CCD camera system or have suggestions on how to improve it please don t fail to contact us We appreciate all your comments and suggestions Additionally if you are interested in writing software supporting SBIG cameras we offer technical support regarding our file formats found in Appendix B and Page 61 Section 6 Accessories for your CCD Camera Technical Notes regarding the camera command protocol which we will make available upon request Page 62 Section 8 Glossary 7 Common Problems This section discusses some of the more common problems others have encountered while using our CCD cameras You should check here if you experience difficulties and if your problem still persists please contact us to see if we can work it out together Achieving Good Focus Achieving a good focus is one of the most difficult areas in working with CCD cameras due to the lack of real time feedback when focusing Focus can take a good deal of time and as with all forms of imaging focus is critical to getting the most out of your camera Once you have achieved a good focus with your system it can be very useful for future observing sessions to scribe an eyepiece or mark down or log positions of each component so the next time you will at least be close to focus at the start If you know where the focal pla
95. se cameras have temperature regulation they still can only cool a fixed amount below the ambient temperature 30 to 40 C Lowering the ambient temperature allows the cameras to achieve lower setpoint temperatures CCD Frosts If your camera starts to frost after a year of use it s time to regenerate the desiccant as described in Appendix C This is a simple matter of unscrewing the desiccant container and baking it without the little O ring in an oven at 350 F for 4 hours No Image is Displayed Try the Auto Contrast setting or use the crosshairs to examine the image pixel values and pick appropriate values for the Background and Range parameters Horizontal Faint Light Streaks in Image some PCs apparently have the mouse generate non maskable interrupts when moved These interrupts can slightly brighten the line being read out If this occurs do not move the mouse during read out Page 64 Section 8 Glossary 8 Glossary Antiblooming Gate When a CCD pixel has reached its full well capacity electrons can effectively spill over into an adjoining pixel This is referred to as blooming Kodak CCDs with the antiblooming option can be used to help stop or at least reduce blooming when the brighter parts of the image saturate Astrometry Astrometry is the study of stellar positions with respect to a given coordinate system Autoguider All SBIG CCD cameras have auto guiding or Star Tracker functions This is accomplished
96. star s position and hence guiding error and corrects the telescope The Track and Accumulate command discussed in section 3 9 2 also has provisions for making telescope corrections between images This is necessary only if your drive has a large amount of long term drift which results in Track and Accumulate images that are reduced in width Finally the Tracking Parameters command allows you to fine tune the CCDOPS tracking performance You can deactivate the RA or DEC corrections or even deactivate both a feature that can be used to monitor the uncorrected tracking accuracy of your drive You can also fine tune the correction speeds if you find the telescope is consistently over or under correcting Page 57 Section 6 Accessories for your CCD Camera 6 Accessories for your CCD Camera This section briefly describes the different accessories available for your CCD camera 6 1 Water Cooling Your camera is equipped with a new heat exchanger design that is ready to accept water circulation for additional cooling efficiency if needed in warm climates The camera can be used either with or without flowing water Water cooling is probably not necessary for most users when the air temperature is below 10 degrees C 50 degrees F since the dark current is fairly low already Think of it as a summertime accessory We do not recommend use of water cooling below freezing temperatures where antifreeze must be added to the water It is simply
97. sub frame images to save disk space if you don t need the full field of view 3 9 6 Color Imaging The field of CCD color imaging is relatively new but expanding rapidly Since all SBIG cameras are equipped with monochromatic CCDs discriminating only light intensity not color some provision must be made in order to acquire color images SBIG offers a color filter wheel the CFW 8 which provides this capability for the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM The color filter wheel allows remotely placing interference filters in front of the CCD in order to take multiple images in different color bands These narrow band images are then combined to form a color image With the SBIG system a Red Green and Blue filter are used to acquire Page 41 Section 3 At the Telescope with a CCD Camera three images of the object The resulting images are combined to form a tri color image using CCDOPS CCDSoftV5 or third party software Color imaging places some interesting requirements on the user that bear mentioning First many color filters have strong leaks in the infrared IR region of the spectrum a region where CCDs have relatively good response If the IR light is not filtered out then combining the three images into a color image can give erroneous results If your Blue filter has a strong IR leak quite common then your color images will look Blue For this reason SBIG incorporates an IR blocking filter stack with the t
98. t consists of a lens mounted in a cell and is usually placed in front of an eyepiece or camera With the relatively small size of CCDs compared to film focal reducers are often used in CCD imaging Frame Transfer CCDs Frame Transfer CCDs are CCDs that have a metal mask over some portion usually half of the pixel array The unmasked portion is used to collect the image After the exposure is complete the CCD can very quickly shift the image from the unmasked portion of the CCD to the masked portion thus protecting the image from light which may still be impinging on the CCD This acts as an electronic shutter Full Well Capacity Full Well Capacity refers to the maximum number of electrons a CCD pixel can hold This number is usually directly proportional to the area of the pixel Histogram The Histogram is a table of the number of pixels having a given intensity for each of the possible pixel locations of the image file Remember that in the end the image file is nothing more than a list of pixel values one for each CCD pixel These value numbers can be displayed in two formats as a table or plotted as a graph Light Frame The Light Frame is the image of an object before a Dark Frame has been subtracted Photometry Photometry is the study of stellar magnitudes at a given wavelength or bandpass Pixel Size The smallest resolution element of a CCD camera is the CCD pixel The pixel sizes for each of the SBIG cameras are as
99. te T shirt worn by the operator Take care that no apparent shadows are cast onto the larger flat white surface Use an exposure at the camera that yields an average light level equal to about half of full scale Page 72 Appendix D Use and Maintenance of the Cooling Booster D Appendix D Use and Maintenance of the Cooling Booster The cooling booster was an option or included accessory for the parallel versions of the ST 7E ST 8E ST 9E ST 10E and ST 10XME When a parallel camera with this accessory is upgraded to the USB version the cooling booster is left in place instead of changing to the new cooling design The cooling booster is a second TE cooling module that goes inside the back compartment of the camera It requires a second power supply This memo is a step by step guide to using the booster for those upgraded cameras that kept the earlier design CAUTION Please be sure that whenever the cooling booster is on i e plugged into 12VDC the camera is also powered up so that the fan is running The fan is needed to dissipate the heat generated by the cooling booster If you power up the booster by plugging it into 12VDC without the camera fan running it can overheat and damage the cooling booster system This won t happen immediately if you happen to accidentally power up the booster before turning on the camera but running it more than few minutes without the fan could damage the unit For users with fixed sites or small obser
100. ted another ease of use feature we employ in the design of our cameras Using a rechargeable desiccant in the chamber keeps the humidity low forcing the dew point below the cold stage temperature Other elements in the self contained ST 7XE ST 8XE ST 9XE ST 10XE ST 10OXME and ST 2000XM include the preamplifier and an electromechanical shutter The shutter makes taking dark frames a simple matter of pushing a button on the computer and provides streak free readout Timing of exposures in ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM cameras is controlled by this shutter The Clock Drivers and Analog to Digital Converter interface to the CCD The Clock Drivers convert the logic level signals from the micro controller to the voltage levels and sequences required by the CCD Clocking the CCD transfers charge in the array and is used to clear the array or read it out The Analog to Digital Converter A D digitizes the data in the CCD for storage in the Host Computer The micro controller is used to regulate the CCD s temperature by varying the drive to the TE cooler The external Power Supply provides 5V and 12V to the cameras Finally the Page 28 Section 2 Introduction to CCD Cameras cameras contain a TTL level telescope interface port to control the telescope and the optional CFW 6A motorized color filter wheel Although not part of the CCD Camera itself the Host Computer and Software are an integral part of the system SB
101. this equipment You are also warned that any changes to this certified device will void your legal right to operate it OPERATION Manual for ST XE ST 8XE ST 9XE ST 10XE ST 10XME ST 2000XM Revision 1 4 June 2004 Section 1 Introduction Cooling Double Page 1 Section 1 Introduction Tri color Ima Camera Lens Ada Page 2 Section 1 Introduction 1 Introduction Congratulations and thank you for buying one of Santa Barbara Instrument Group s CCD cameras The model ST 7XE XME ST 8XE ST 9XE ST 10XE XME and ST 2000XM XCM are SBIG s fifth generation CCD cameras and represent the state of the art in CCD camera systems with their low noise and advanced capabilities including Kodak s new Blue Enhanced E series of CCDs and high speed USB interface We feel that these cameras will expand your astronomy experience by being able to easily take images like the ones you ve seen in books and magazines of structure never seen through the eyepiece SBIG CCD cameras offer convenience high sensitivity and advanced image processing techniques that film just can t match While CCDs will probably never replace film in its large format CCDs allow a wide range of scientific measurements and have established a whole new field of amateur astronomy that is growing by leaps and bounds These cameras include several exciting new features improved self guiding US Patent 5 525 793 high speed USB interface improved cooling design and more
102. though Using an ST 7XE or ST 8XE camera with their 9 micron pixels an 8 10 telescope will produce a single pixel angular subtense of 0 9 arcsecond An 8 f 4 telescope will produce images of 2 5 arcseconds per pixel If seeing affects the image by limiting resolution to 6 arcseconds you would be hard pressed to see any resolution difference between the two focal lengths as you are mostly limited by the sky conditions However the f 4 image would have a larger field of view and more faint detail due to the faster optic The ST 9XE with its 20 micron pixels would have the same relationship at roughly twice the focal length or a 16 inch f 10 telescope See table 4 4 for further information A related effect is that at the same focal length larger pixels collect more light from nebular regions than small ones reducing the noise at the expense of resolution While many people think that smaller pixels are a plus you pay the price in sensitivity due to the fact that smaller pixels capture less light For example the ST 9XE with its large 20 x 20 micron pixels captures five times as much light as the ST 7XE and ST 8XE s 9 micron square pixels For this reason we provide 2x2 or 3x3 binning of pixels on most SBIG cameras With the ST 7XE and ST 8XE for instance the cameras may be configured for 18 or 27 micron square pixels Binning is selected using the Camera Setup Command It is referred to as resolution High 91 pixels Medium 182 pixels Lo
103. ting circle on the known object s RA and note any DEC errors Reposition the telescope at the intended object using the correct RA setting and the same DEC offset noted with the calibration object Try a ten second or one minute exposure and hopefully you will have winged the object If not you will have to hunt around for the object You can use the Focus mode in Low resolution mode for this and hopefully you won t have to search too far Check in DEC first as DEC setting circles are often smaller and less accurate Telescope Port doesn t Move Telescope If you find the camera is not moving the telescope for Tracking Track and Accumulate or Self Guiding you should use the Move Telescope command with a several second period to isolate the problem down to a specific direction or directions If you set the Camera Resolution to the Low mode in the Camera Setup Command you can move the telescope and Grab an image fairly quickly to detect movement of the telescope pointed at a moderately bright star Try each of the four directions and see which ones move and which ones don t At this point the most likely culprit is the hand controller modification Trace the signals from the camera s telescope connector back through the hand controller paying particular attention to the offending wires Can t Reach Low Setpoint Temperatures If you find that the camera isn t getting as cold as expected the problem is probably increased ambient temperatures While the
104. tire array shifts up one row when a row is shifted into the readout register and a blank row is inserted at the bottom The electromechanical shutter built into the camera covers the CCD during the readout to prevent streaking of the image Without a shutter the image would be streaked due to the fact that the pixels continue to collect light as they are being shifted out towards the readout register CCDs with a single active area are called Full Frame CCDs For reference the ST 5C ST 237A STV and guiding CCDs in the ST X series of cameras use a different type of CCD which is known as a Frame Transfer CCD In these devices all active pixels are shifted very quickly into a pixel array screened from the light by a metal layer and then read out This makes it possible to take virtually streak free images without a shutter This feature is typically called an electronic shutter The interline CCD used in the ST 2000XM is similar to a frame transfer except that the protected pixels are interlaced with the active pixels 2 3 Camera Hardware Architecture This section describes the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME and ST 2000XM CCD cameras from a systems standpoint It describes the elements that comprise a CCD camera and the functions they provide Please refer to Figure 2 2 below as you read through this section 1 History and Advancements of Large Area Array Scientific CCD Imagers James Janesick Tom Elliott Jet Propulsion Laboratory C
105. to allow the enclosed spaces to dry out and minimize long term corrosion A 110VAC to 12VDC transformer is supplied with the cooling booster The booster requires approximately 2 amps at 12VDC If you wish to connect direct to 12VDC please note polarity of the DC Power Jack on back plate of camera The power jack is electrically isolated from the camera body 12VDC on outside Ground in Center Mating plug is 5 5mm outside and 2 1mm inside Figure A DC Power Jack Page 74 Appendix E Third Party Vendors Supporting SBIG Products E Appendix E Third Party Vendors Supporting SBIG Products Company Author Software Bisque CCDSoftV5 912 12th Street Golden CO 80401 1114 USA TheSky Sales 800 843 7599 International 303 278 4478 Orchestrate Facsimile 303 278 0045 T point Camera control Image Processing Astrometry Minor Planet Searches Planetarium and Charting Scripting Remote operation and E mail Sales bisque bisque com Paramount telescope control Robotic mounts E mail Support support bisque com Web site Authorized SBIG Dealer Diffraction Ltd Maxim Image Processing 100 Craig Henry Drive DL CCD Camera Control software Unit 106 Ottawa ON K2G 5W3 Canada Authorized SBIG Dealer Telephone 613 225 2732 FAX 613 225 9688 E mail Sales E mail Support Web site www cyanogen com Axiom Research Mira Camera control Image 1830 East Broadway Blvd Suite 124 202 software processing
106. toelectric effect when photons or particles strikes certain materials free electrons are liberated In the second step the photoelectrons are collected in the nearest discrete collecting sites or pixels The collection sites are defined by an array of electrodes called gates formed on the CCD The third operation charge transfer is accomplished by manipulating the voltage on the gates ina systematic way so the signal electrons move down the vertical registers from one pixel to the next in a conveyor belt like fashion At the end of each column is a horizontal register of pixels This register collects a line at a time and then Page 25 Section 2 Introduction to CCD Cameras transports the charge packets in a serial manner to an on chip amplifier The final operating step charge detection is when individual charge packets are converted to an output voltage The voltage for each pixel can be amplified off chip and digitally encoded and stored in a computer to be reconstructed and displayed on a television monitor Readout Register Y 1 pope Amplifier Output Y N epee eee Figure 2 1 CCD Structure 2 2 1 Full Frame and Frame Transfer Interline CCDs In the ST 7XE ST 8XE ST 9XE ST 10XE and ST 10XME the CCD is read out electronically by shifting each row of pixels into a readout register at the Y 0 position of the CCD shown in Figure 2 1 and then shifting the row out through an amplifier at the X 0 position The en
107. ue to Dark Noise is related to just two parameters integration time and temperature of the CCD The longer the integration time the greater the dark current buildup Conversely the lower the operating temperature the lower the dark current This is why the CCD is cooled for long integration times Dark noise is a mostly repeatable noise source therefore it can be subtracted from the image by taking a Dark Frame exposure and subtracting it from the light image This can usually be done with very little loss of dynamic range Double Correlated Sampling Double Correlated Sampling DCS is employed to lower the digitization errors due to residual charge in the readout capacitors This results in lower readout noise False Color False Color images are images that have had colors assigned to different intensities instead of gray levels FITS Image File Format The FITS image file format which stands for Flexible Image Transport System is a common format supported by professional astronomical image processing programs such as IRAF and PC Vista CCDOPS can save image files in this format but can not read them Page 65 Section 8 Glossary Flat Field A Flat Field is a image with a uniform distribution of light entering the telescope An image taken this way is called a flat field image and is used with CCDOPS to correct images for vignetting Focal Reducer A Focal Reducer reduces the effective focal length of an optical system I
108. urpose 3 5 Finding and Centering the Object Once best focus is achieved we suggest using Dim mode to help center objects This mode gives a full field of view but reduces resolution in order to increase the sensitivity and digitization and download rate If you have difficulty finding an object after obtaining good focus check to be sure that the head is seated at best focus then remove the head and insert a medium or low power eyepiece Being careful not to adjust the focus knob on the telescope slide the eyepiece in or out until the image appears in good focus Then visually find and center the object if it is visible to the eye If not use your setting circles carefully Then re insert the CCD head and use FOCUS mode with an exposure time of about ten seconds if it is dim Center the object using the telescope hand controls Note With a 10 second exposure objects like M51 or the Ring Nebula M57 are easily detected with modest amateur telescopes The cores of most galactic NGC objects can also be seen 3 6 Taking an Image Take a CCD image of the object by selecting the Grab command and setting the exposure time Start out with the Image size set to full and Auto Display and Auto contrast enabled The camera will expose the CCD for the correct time and digitize and download the image One can also take a dark frame immediately before the light image using the Grab command Because the ST 7XE ST 8XE ST 9XE ST 10XE ST 10XME
109. us command automatically displays successive images on the screen as well as the peak brightness value of the brightest object in the field of view Point the telescope at a bright star Center the star image in the CCD and adjust the focus until the star image is a small as can be discerned Next move the telescope to a field of fainter stars that are dimmer so the CCD is not saturated Further adjust the focus to maximize the displayed star brightness in counts and minimize the star diameter This can be tedious It helps considerably if a pointer or marker is affixed to the focus knob so you can rapidly return to the best focus once you ve gone through it An exposure of 1 to 3 seconds is recommended to smooth out some of the atmospheric effects While you can use the Full frame mode to focus the frame rate or screen update rate can be increased significantly by using Planet mode In Planet mode the Focus command takes a full image and then lets you position a variable sized rectangle around the star On subsequent images the Planet mode only digitizes downloads and displays the small area you selected The increase in frame rate is roughly proportional to the decrease in frame size assuming you are using a short exposure The telescope focus is best achieved by maximizing the peak value of the star image You should be careful to move to a dimmer star if the peak brightness causes saturation The saturation levels of the various resolution modes a
110. vatories water circulation and the attendant tubes and pump are easier to manage For field use however you may wish to forgo water circulation and use the cooling booster with 12VDC only to simplify the setup When using water circulation the major problem one must deal with is routing the rather heavy water tubes off the mount to minimize perturbations to the mount during tracking In general try to route tubes and wires over the mount rather than just let the tubes dangle from the end of a long tube Water cooling is probably not necessary for most users when the air temperature is below 10 degrees C 50 degrees F since the dark current is fairly low already Think of it as a summertime accessory We do not recommend use of water cooling below freezing temperatures where antifreeze must be added to the water It is simply not necessary then There is no problem with using the cooling booster with only air cooling in the winter though With the cooling booster installed on your camera you have a choice of three levels of cooling First you can ignore the booster and operate the camera with single stage cooling only by simply not connecting 12VDC to the booster s power plug Second with the camera power on and fan funning you can also power up the cooling booster by plugging in 12VDC to increase the cooling capability of the camera without using any water circulation Third you can power up the cooling booster with 12VDC and use water circu
111. ver for this device To install the driver Windows found click Next chprogram fles sbighdriver checkerksbig drivers sbigusbe int Click the Next button Page 20 Section 1 Introduction 7 Windows will spin for a while then present you with the dialog below Click the Finish button and you re done The SBIG cameras actually use two drivers and after you click Finish the system will automatically install the second driver Found New Hardware Wizard Completing the Found New Hardware Wizard O SBlG USE Loader Windows has finished installing the software for this device To close this wizard click Finish Page 21 Section 1 Introduction 1 2 3 Getting Started with CCDOPS e Use Camera gt Establish Com Link After a few seconds should see Link ST 10 USB in lower right corner of CCDOPS main window where ST 10 is the camera model You are now talking to the camera e From this point you should follow the software instructions help menus to Set Up the camera s cooling Focus Grab images etc 1 2 4 To try some functions with sample images e Double click on the CCDOPS icon to launch the program e Use the Open command in the File menu to load one of the sample images A window showing the exposure time etc will appear Click in it to make it disappear The image will show up in its own window e Try using the crosshairs Use the Crosshairs command in the Display menu e Use the
112. w 2712 pixels When binning is selected the electronic charge from groups of 2x2 or 3x3 pixels is electronically summed in the CCD before readout This process adds no noise and may be particularly useful on the ST 10XE with its very small 6 8 micron pixels Binning should be used if you find that your stellar images have a halfwidth of more than 3 pixels If you do not bin you are wasting sensitivity without benefit Binning also shortens the download time The halfwidth of a stellar image can be determined using the crosshairs mode Find the peak value of a relatively bright star image and then find the pixels on either side of the peak where the value drops to 50 of the peak value taking the background into account if the star is not too bright The difference between these pixel values gives the stellar halfwidth Sometimes you need to interpolate if the halfwidth is not a discrete number of pixels Another important consideration is the field of view of the camera For comparison the diagonal measurement of a frame of 35mm film is approximately 43mm whereas the diagonal dimension of the ST 7XE chip is approximately 8 mm The relative CCD sizes for all of the SBIG cameras and their corresponding field of view in an 8 f 10 telescope are given below Page 31 Section 2 Introduction to CCD Cameras Camera Array Dimensions Diagonal Field of View at 8 10 TC211 Tracking CCD 2 64 x 2 64 mm 3 73 mm 4 5 x 4 5 arcminutes TC237 Tracking CCD
113. w highlights the differences from a system s standpoint A D Temperature Electromechanical Electronic Camera Resolution Regulation Shutter Shutter Shutter Wheel Vane ST 5C 16 bits Closed Loop Shutter Wheel 0 01 second ST 237A 16 bits Closed Loop Shutter Wheel 0 01 second STV 10 2 bits Closed Loop Shutter Wheel 0 001 second ST 6 16 bits Closed Loop Vane 0 01 second ST 7 8 9 10 1001 2000 16 bits Closed Loop Shutter None Table 4 2 System Features How these features affect the average user are discussed in the paragraphs below A D Resolution This is a rough indication of the camera s dynamic range Higher precision A D Converters are able to more finely resolve differences in light levels or for larger CCDs with greater full well capacities they are able to handle larger total charges with the same resolution Temperature Regulation In an open loop system like the original ST 4 the CCD cooling is either turned on or turned off While this provides for adequate cooling of the CCD the CCD s temperature is not regulated which makes it important to take dark frames in close proximity to the associated light frame Closed loop systems regulate the CCD s temperature to an accuracy of 0 1 C making dark frames useful over longer periods Electromechanical Vane Having the vane in the ST 6 means the host software can effectively cover the telescope and take dark frames remotely without the user having to get up and physically cover t
114. x3 to 31x31 pixels to collect all the energy from a star 3 9 2 Sub Frame Readout in Focus The Focus command offers several frame modes for flexibility and increased frame throughput As previously discussed the Full frame mode shows the entire field of view of the CCD with the highest resolution digitizing and displaying all pixels The Dim mode offers the same field of view but offers higher frame rates by reducing the image s resolution prior to downloading The resolution is reduced by combining a neighboring block of pixels into a super pixel This reduces the download and display times proportionately as well as improving sensitivity It is great for finding and centering objects The Planet mode is suggested if high spatial resolution is desired for small objects like planets The Planet mode allows you to select a small sub area of the entire CCD for image acquisition The highest resolution is maintained but you don t have to waste time digitizing and processing pixels that you don t need Again the image throughput increase is proportional to the reduction in frame size It can be entered from Auto mode Page 39 Section 3 At the Telescope with a CCD Camera Another aspect of the Focus command and its various modes is the Camera Resolution setting in the Camera Setup command Briefly the Resolution setting allows trading off image resolution pixel size and image capture time while field of view is preserved High resolution

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