User Manual - Innovations Foresight
Contents
1. ONAG Patent Pending O 2 K Innovations Foresight O o lt nme Revision 5 1 ONAG Standard SC and XT ON Axis Guider User Manual Rey 5 1 2011 Innovations Foresight LLC http www innovationsforesight com versions with guider drawtube and helical focusers 2011 Innovations Foresight LLC http www innovationsforesight com Introduction Thank you for purchasing our patent pending on axis guider ONAG Ours product have been designed and made with care to give its user the highest level of experience and satisfaction Please take a moment to read this manual in order to get the most of your ONAG refer to section 7 for pictures of the standard ONAG and its parts See section 9 for the ONAG XT specifics and section 10 for the ONAG SC specifics Please note this product was not designed or intended by the manufacturer for use by child 12 years of age or younger Also please do not look at the sun or any bright light sources laser with your ONAG even at the guider port The ONAG comes in several versions The standard ONAG and ONAG SC uses a M42 x 0 75mm thread T mount system and have been optimized for CCD imagers using large format APS C chips up to 28mm in diagonal The ONAG SCT features a dovetail based X Y stage as well as a helical guider focuser other specifications and uses are identical to the standard ONAG The ONAG XT supports2. see low profile section 3 2 2 below With the standard configuration the X YS can be used alone to search for a guide star across the full field of view When used in conjunction with ONAG body rotation you can achieve up to 23 mm of off axis offset both X and Y axis at travel ends However this configuration leads to more total optical back focus TOBF 1 2 2 Low profile configuration In low profile configuration the Y axis travel is limited as follow With a 8 mm extension tube there is 16 8 8 mm reduction of Y axis upper portion travel With no extension tube there is no travel on the upper Y axis portion anymore Any configuration below 16 mm will restrict the travel by Travel restriction mm 16 X Where X is the length X lt 16 mm of the extension used in mm In the low profile configuration the lower portion of the Y axis travel and all the X axis travel range are fully usable Therefore a rotation of the ONAG up to 180 degrees will allow access to the full field of view when searching a guide star What is left of Y axis travel combined with the X axis and the ONAG rotation provides again an exploration circle up to 46 mm in diameter The low profile configuration is recommended if a short TOBF is desired see table on section 3 1 2 Using the ONAG The use of the ONAG is quite simple First focus both cameras next you select a guide star and then you are ready for a normal imaging session us
3. Fully multi coated Optical grade quartz gt 98 typical gt 370 nm to 750 nm gt 90 typical gt 750 nm to 1200 nm Black low reflection As with any high quality optical device the ONAG should be handled with care Do not drop the ONAG or submit it to excess vibrations or temperature The ONAG has been assembled with precision to insure accurate alignment of the dichotic beam splitter DBS in relation with all the optical ports therefore resist disassembling the ONAG body ONAG User Manual rev 5 1 36 2011 Innovations Foresight LLC Doing so may result in image distortion due to misalignments but also will void the warranty The scope port SP provides a standard female T thread for mounting the standard and SC ONAG to a scope or another device be sure when you screw any equipment there that the associated male T thread length will not interfere with the dichroic beam splitter DBS Failure to do so may scratch the DBS surface As guidance only you may want the male T thread no longer than 5mm If longer then consider using a T ring to control the thread penetration depth The ONAG XT female 2 adapter as a usable 30mm depth be sure that you do not exceed this length otherwise you may touch and damage the dichroic mirror The guider focuser GF drawtube for the ONAG XT and standard versions have two grooves and there are two associated nylon screws 6 32 see section 6 on the focuser comp
4. visible light is reflected there is no optical aberration involved here The guide star may look like a tight cross since there is some astigmatism coming from the fact that the starlight traveled through the DBS sets at 45 degrees Yet the DBS is only few millimeters thick and its effect does not impact popular auto guider software like Maxim DL GuideDog PHD guiding or software using centroid algorithms to track the guide star s The guide star half flux diameter HFD is essentially similar for the imager and guider cameras resulting to a negligible change in SNR if any Using NIR for guiding reduces the seeing effect which in turn provides tighter guide stars and better SNR this offsets also part of the energy drop coming from the use NIR The guide star astigmatism is a function of the scope focus position in or out and this information is used by our real time auto focus system SL ONAG User Manual rev 5 1 2 2011 Innovations Foresight LLC ONAG Transmission coating Visible 350 to 750nm 771 56 90 797 1101 5 94 396 NIR 709 11 3 7203 750 to 1800nm 370 823 0011 577 96 A7T466 449 93_047716 ONAG spectral response Imager to 750 nm from 370nm Scope Guider gt 750 nm ONAG basic principle 2 A scope port SP The SP allows the standard and SC ONAG to be attached to any scope using a standard T threaded female connection T mount M42 x 0 75 or a 59mm dovetail sy
5. Innovations Foresight LLC 8 ONAG and tracking software some considerations Although the ONAG solves differential flexure problems while featuring a wide field of view to locate a suitable guide star the tracking software is also a key element in the all process of auto guiding It is paramount to understand its basic operation and choose the right software settings to achieve good image quality There are many tracking software available such as Maxim DL PHD guiding GuideDog to name few They typically use centroid algorithms averaging pixel values all around the guide star area to estimate its position with sub pixel accuracy The guide star shape does not matter much as long as it is not clip consistent across frames and is not too much spread or fain For that matter the little cross shape of the guide star seen from the ONAG GP in NIR does not impact the software tracking capability Guiding with the ONAG means using the same focal length than imaging and unlike guide scopes this translates most of the time to a small field of view especially for long focal scopes Meaning for each guide star frame we may expect having more seeing effect and other short term perturbation contributions Therefore most of the time it 1s recommended to bin the guider image by 2x or 3x which will average nearby pixels unless the guider pixel size is much great than the imager one 4x or above This can be seen as a low pass filter operation
6. ONAG User Manual rev 5 1 28 2011 Innovations Foresight LLC bright stars Those outliers are more likely if Gy 1s large They may also come from some mechanical problems such as over compensated backlash by the mount software If your mount is equipped with a periodic error correction PEC you should use it We also recommend unbalancing just a little your mount in AR making it East heavy to avoid any backlash on the RA axis Be aware this must be done differently for both meridians on equatorial mounts Backlash compensation done by most mount software may result 1f too large in bumping the mount especially on DEC axis equatorial mounts for which the drive motor can reversed it direction Yet too little backlash compensation leads to lag in the correction and erratic tracking If you have difficulties to solve this DEC problem you can use a simple technique Just disturb a little bit the mount polar alignment this will result in a single direction DEC drift the DEC drive motor does not need to reverse anymore avoiding backlash issues Most software allows disabling either correction direction in AR and DEC use this feature when available You need just a very little polar alignment error to accomplish this trick Do not misalign your mount too much otherwise long exposures may exhibit field rotation If this is your first experience with guiding at the same focus than imaging you will need some time to find the right settin
7. full frame CCD such as the 24mm x 36mm format and more up to 50mm in diagonal and it uses a dovetail system for the scope and imager optical ports For more information concerning the ONAG products and imaging camera sensor chip illuminations please visit us at http www sbdcdev com ifi support onag xt ccdcmos chip illumination Searching for a suitable guide star has never been easier thanks to the ONAG wide field of view and convenient quick set up X Y stage providing an exploration circle up to 46 mm 1 8 in diameter This is more than 1 3 arc degrees for two meters focal length scope Also there is no need to rotate for searching a guide star this allows reusing your flat frames for many targets and nights Because it uses the same scope and optical train as your imager there is no differential flexure The ONAG shares the same focal ratio F number and aperture as your scope set up providing maximum light to the guiding camera Since filters and filter wheels are placed in the imager optical path they will not interfere with the guider camera Therefore even narrow band imaging will not make the guide star s too dim to use anymore The ONAG is made of high quality aluminum and stainless steel material Its optical dichroic beam splitter DBS 1s fully multi coated and protected with a transparent layer of quartz for a long life The use of near infrared NIR for guiding decreases significantly the effect of the Eart
8. images even out of focus like donuts The HFD varies linearly with focus position making it reliable to locate the best focus regardless the star shape If you use the PHD guiding software watch the SNR value you should seek for its maximum If you do not use any software the best focus will be achieved when the guide star cross like shape is minimized and symmetric The two images below show the same guide star seen from the imager IP ONAG User Manual rev 5 1 13 2011 Innovations Foresight LLC on the left or from the guider GP on the right at best focus same camera set up and cropping Guide star seen from IP Guide star seen from GP HFD 6 0px FWHM 3 4px HFD 6 2px FWHM 5 2px The cross like shape of the guide star viewed from the GP is clearly visible Yet as far as the energy budget is concerned both cases have almost the same HFD The GP larger FWHM is due to the star non circular shape During this focusing process avoid to over exposing the guide star Doing so will bias the HFD values and make the star shape more difficult to guess for accurate focus Bright over expose stars may result in ghost images offset by few millimeters hundreds of pixels Those are reflections from the DBS and nearby surfaces such as the CCD camera windows Most optic are not coated for NIR The reflections are out of focus and will look like faint stars with donuts like shapes This is not issue When you reached the desired focu
9. initial focus position Therefore in this context the best procedure calls for recording how much you could rotate further from the best focus after you tighten the focuser locking screw then back off to the best focus position ONAG User Manual rev 5 1 34 2011 Innovations Foresight LLC Now unlock the focuser locking screw and continue to back off the focus ring by the recorded amount above Finlay lock the focuser locking screw and rotate the focuser ring to the best focus position again 11 Use of a 114 nosepiece with a helical focuser The ONAG SC and the ONAG XT guider helical focusers cannot be removed and replaced by a 1 25 guider camera or nosepiece However a 1 25 nosepiece or guider camera body can be inserted inside the focuser tube There are two UNC 4 40 stainless set screws to secure it in place The image below shows the focuser tube with its male T thread T2 M42 x 0 75mm and the location of both set screws UNC 4 40 SS UNC 4 40 set screw i I i E raa E a a set screw ONAG guider helical focuser and its set screws Depending of the version of the helical focuser the nosepiece depth is between 10mm to 20mm Using this configuration especially with 1 25 guider cameras offers the opportunity to decrease the guiding camera backfocus Alternatively you can use a T mount M42 x 0 75mm to 1 25 adapter to connect your device Such adapter can be order from various third party supplie
10. limiting seeing and chasing the noise like guide star motion at each frame Yet the most important single parameter of any tracking software is the aggressiveness which is the level of correction the algorithm will apply to the mount after each new guide star frame In control system theory close loop systems this is known as the feedback gain Gr If it is too low the correction is not enough to compensate for the mount drift In the other hand 1f Gr is too large the correction will become instable and erratic The later is the most problematic and common issue in tracking leading to elongated star in the images even with near perfection optics From the above considerations we recommend you start with a low aggressiveness 1 2 or 50 or less to begin with and increase it slowly only if you have to For instance for Maxim DL this means 5 in PHD guiding this would translate to 50 for both cases it is half way to full scale correction 1 or 100 or less A common figure of merit for the tracking error quality evaluation is the rms root mean square error value over a time window However even with a low error value you still may experience elongated stars Very often bright stars are much brighter than the target under consideration for your imaging session such as galaxy or nebulas During several minute of exposure a short extreme erratic tracking correction during a second or so way above the rms value will be enough to distort the
11. BF The IPBF is defined has the back focus or distance in mm between the ONAG IP top of the ONAG body and the imaging camera chip image plane For an optical train and scope point of view the total optical back TOBF focus including the ONAG and the imager its accessories filter wheel if any is the right figure of merit The TOBF will eventually limit the scope focusing mechanism ability to reach focus The TOBF not including accessories before the ONAG such as a focuser and or AO unit can be estimated with the following formula TOBF IPBF IBF The choice of the right option is a function of the scope performance and requirement In some situations one may want to minimize the TOBF but there are many cases where we may need a larger back focus Most scopes such as SCT are designed for some optimal back focus distances for which they reach their nominal specifications such as focal length F number field of view For instance the Celestron EdgeHD SCT series have a built in corrector and they will provide optimal performance if the focal plane is at or near a predefined distance from the scope visual back According to Celestron http www celestron com c3 support3 index php _m knowledgebase amp _a viewarticl e amp kbarticleid 2260 133 35 mm for 8 EdgeHD SCT 146 00 mm for 9 24 11 and 14 EdgeHD SCT In such case you may even want to add extension tube s on the SP to reach the right dista
12. Innovations Foresight LLC h4 1 112 4 235 0 52x instead of 0 63x a 17 decrease FR in front of ONAG example 1 Reducer Starizona SCT corrector 0 75x DFR 90mm Imager SBIG ST S8300C IBF 17 5mm ONAG in low profile mode Back focus 66m You will need an extension tube of 90 66 17 5 6 5mm to meet the Starizona DER value of 90mm FR in front of ONAG example 2 Reducer Celestron 0 63x f 235mm DFR 87mm Imager QSI 683ws IBF 35 5mm 1 4 ONAG in low profile mode Back focus 66mm q 66 35 5 101 5mm leading to a reduction factor h 1 101 5 235 0 57x 9 larger The second option is to place the FR at the ONAG IP before the imager In this case the ONAG back focus does not play any role anymore We are here in the classical situation However you will have to find the right spacing for reaching focus with your guider by trial and error since the table from section 3 1 above will ONAG User Manual rev 5 1 16 2011 Innovations Foresight LLC not be correct anymore Most likely you will need to use extra extension tubes to move the guider further away from the ONAG body The following relation is useful to guide you through this process p q h Assuming you are in focus at the imager focal plane with the FR in place then p 1s the distance from the FR to the scope focal plane This is the distance where you would be in focus if the FR is removed and the scope focus is left untouched In short wit
13. The three possible options lead to a IPBF 82 mm TOBF 82 52 134 mm 5 28 b IPBF 74 mm low profile configuration see 3 2 TOBE 74 52 126 mm 4 96 c IPBF 66 mm low profile configuration see 3 2 TOBF 66 52 118 mm 4 65 Be aware that option c could prohibit access to some DSLR functions and interface if its body is too close to the ONAG 1 2 Standard versus low profile configuration The ONAG has three effective degrees of freedom for exploring the field of view in search for a guide star The X Y stage X YS provides two orthogonal axis X and Y see section 2 while the rotation of the ONAG body adds a third degree for freedom This gives an overall exploration circle up to 46 mm in diameter and allows the ONAG to be used in different and flexible ways There are two fundamental configurations standard and low profile which can be used to optimize the set up While the X stage axis can always be used at full range there are may be travel limitations for the Y axis please see the section below 1 2 1 Standard profile configuration In the standard configuration the XYS can be fully extended in the upper ONAG User Manual rev 5 1 11 2011 Innovations Foresight LLC Y axis portion positive sense toward the IP see section 2 This is possible only if a 16 mm or more extension tube s 1s attached on the IP Otherwise the XYS will experience limited Y travel toward the IP
14. as been abused mishandled not properly cared of or modified nor does it apply to normal wear and tear This warranty gives you specific legal rights and you may also have other rights which vary from state to state For further warranty service information contact IF http www InnovationsForesight com or 1 215 884 1101 ONAG User Manual rev 5 1 38 2011 Innovations Foresight LLC 15 Registration Prod ct names O ERUEN oaiae EA E SCMaliNUMIDET geen O Deter purchase arpionar a ie TE bee OEE Where did you DUVI aair A E Have you registered with us before YES NO Fitna appn eT a Eas tNames adnenhaldad Mee Aa E bit id am bteads AdS E ehmoen ce aun onaeeanne onsen GE E E A eect ana E E cece State PIOVE sebtesadannechcuuneeaecedcnesceautenmaeaenee A AIE COdes SFOR E E AASS COUNTY ART A duliineetatins Phoned day GING chased ovsianseoseihecncaulvataotwesta E N N ema e A EA Please take a moment to answer the following questions How did you hear about us On which equipment do you plan to use our product Any comments Please copy and send this form to Innovations Foresight 24 Ramblewood Drive Glenmoore PA 19343 United State of America ONAG User Manual rev 5 1 39 2011 Innovations Foresight LLC 16 Glossary AFR Adjustable focal reducer DBF Differential back focus DBS Dichroic beam splitter FR Focal reducer GBF Guider back focus GF Guider focuser GP Guider port IBF Imager back focu
15. astigmatism corrector in place This document and following examples assume a standard or SC ONAG for the XT versions just subtract 2mm with a drawtube focuser and 5mm with a helical focuser from your guiding camera back focus GBF for reusing the following table and calculations There is 26 mm 1 02 difference on back focus between the IP and GP associated with spacers T mount such as the 8mm and 16mm long ones available by Innovations Foresight this allows for a wide range of imager and guider pairs including DSLR Innovations Foresights also provides dovetail extensions tubes 8mm 16mm 24mm long spacers for the SP and IP of the ONAGO XT The key factor here is the differential back focus DBF which is defined as the difference between the imager back focus IBF and guider back focus GBF DBF IBF GBF Most of the time this number is greater than zero but in some configurations it could be negative Of course both back focus values must include any related accessories mounted in series with either camera such as a filter wheel Should you have a focal reducer FR see sections 5 and 6 below The table below provides for convenience the recommended selection of extension tube spacers of 8mm and 16mm long for a correct set up For instance the combination of 8mm 16mm spacers can be replaced by a 24mm spacer All you need is your imager including the filter wheel if any and guider optical back focus val
16. available for the ONAG XT ONAG User Manual rev 5 1 4 2011 Innovations Foresight LLC they are 8 mm 16 mm and 24 mm long The XT dovetail extension tubes are used for the SP and IP however any ONAG versions use a M42 x 0 75mm T mount connection for the GP With the proper combination they allow a wide range of imager including DSLR and guider to reach focus simultaneous see set up section 3 for further information on making cameras parafocal Alternatively they can be used to extend the ONAG back focus when necessary Focuser drawtube P I J 2i Standard ONAG guider focuser and X Y stage ONAG User Manual rev 5 1 Nn 2011 Innovations Foresight LLC 1 Set up For proper operation it is required that cameras imager and guider reach focus simultaneously be parafocal T threaded extension tubes spacers or and dovetail spacers for the ONAG XT are used to conveniently spaced when needed the cameras from the ONAG body There are two low profile T rings for rotating and locking the cameras to the desired positions Alternatively the ONAG XT dovetail system offers a total freedom of rotation for the IP and SP Since the IP and GP male T threads are longer than the extension tube threads it is recommended to use the T rings at those ports Although they could be used with extension tubes as well you may run out of thread length to safely secure the cameras The ONAG is connecte
17. ch as AO unit tighten it If you want to freely rotate the SCT female ring remove and save the screws with a Phillips screwdriver To remove the adapter from the ONAG SP or other accessories put the screws back in place and then unscrew the adapter ONAG User Manual rev 5 1 23 2011 Innovations Foresight LLC 7 ONAG and its parts X Y stage XYS Guider focuser GF 3 k Guider port GP ONAG back view ONAG User Manual rev 5 1 24 2011 Innovations Foresight LLC Imager port IP ae Compression ring ONAG side view Notice New ONAG serial number 4000 and above and the XT version have 4 nylon thumbscrews only The four others are nylon slotted screws which may be adjusted to insure easy smooth stage motion Usually this is done once than the four thumbscrews are more than enough to insure a rigid play free stage when hand tighten ONAG User Manual rev 5 1 25 2011 Innovations Foresight LLC Focuser screw E i pa E N Scope port SP ONAG front view SCT adapter ring SCT adapter core SCT adapter screws SCT lower profile adapter ONAG User Manual rev 5 1 26 2011 Innovations Foresight LLC E e a _ lt a wi ONAG mounted on Celestron 8 orange tube with SBIG ST2000XCM imager and Orion StarShoot autoguide ONAG User Manual rev 5 1 2J 2011
18. d to your scope using the SP It is highly recommended to use a rigid assembly such as the T thread the SCT adapter or a 2 adapter with a compression ring on the scope side Alternatively you can get custom adapters for any ONAG from our partner preciseparts www preciseparts com Innovations foresight offers also 2 nosepiece and SCT adapters for every ONAG version The ONAG DBS has been laser aligned with care and precision for providing the best results however an inappropriate user set up could impact significantly the image quality Thumb screen set ups may result on poor optical alignment leading to tilt of the camera focal plane and distorted star across the image Therefore they are not encouraged we recommend using rigid connection such as threads and compressing rings It is not recommend that user touch any of the ONAG mirror adjustment mechanism our product have been aligned at factory therefore please do not try to do so you will upset the factory adjustment and you may void the warranty ONAG User Manual rev 5 1 6 2011 Innovations Foresight LLC 1 1 Differential back focus The standard and SC ONAG have 66 mm 2 6 of optical back focus from the SP front plate to the IP T thread and 92 mm 3 62 from the SP to the GP when the GF drawtube is half way extended The ONAG XT has an IP backfocus of 68mm and the same GP back focus of 92mm with the GP drawtube half way extended and the GP
19. e None 2x16 2x8 16 2x8 1648 1648 1648 E l6 None o E Non GP Extension Tube s mm None None None None None 16 2x8 16 8 16 2x8 16 8 2x16 8 16 2x8 2x16 8 2x16 2x8 None 114 _ Noe 8 8 80 16 8 ee ee ee o i6 9 1648 82 l6 4 16 2x8 82 66 6 16 2x8 4 2x168 4 2x16 8 6 IP Back Focus IPBF mm 114 106 Comment DBF lt 0 DBF lt 0 DBF lt 0 82 J o 82 o 74 Low profile Low profile 82 o 74 Low profile Low profile S20 74 74 74 Recommended extension tube v s differential back focus DBF ONAG User Manual rev 5 1 2011 Innovations Foresight LLC Although the table provides a good indication for selecting the extension tubes it is only a recommendation Actual device back focus values from manufactures may deviate from their specification or may vary over time without warning Other elements such as filter thickness and mechanical connections could impact the final set up as well Since most likely your DBF will not be in the table the normal course of action is to look in the table for the closest DBF yet some time the one below or above could be necessary For some DBF values there are several options Either of them will allow both cameras to reach focus simultaneously however some may require using the ONAG low profile configuration see section 3 2 They also differ on IP back focuses IP
20. e X see the AFR parts and nomenclature figure above The required X value is given by the following relation X qarr GBF With GBF your guider back focus and qarr q h 102 q h 102 the required AFR back focus Where q in mm and h are your imager FR back focus most likely q DFR and its reduction factor respectively See your FR specifications and user manual for those values By the way the above SCT comment does not apply here By adding when necessary one or more ONAG T threaded extension tubes 8 16 24mm you have access to a large range of AFR extension value X listed in the table below Extension Tube s AFR extension value ranges v s extension tubes ONAG User Manual rev 5 1 20 2011 Innovations Foresight LLC Select a suitable range from the table and adjust the AFR focusing ring to bring the AFR extension length close to the selected X value with the extension tube s if any You can use a ruler to help Now focus the guider using the AFR focusing ring you may have to adjust the ONAG X Y stage to center the star When done secure the AFR focusing ring associated plastic screw Fine focus can be achieved with the ONAG guider focuser if necessary Now you are ready to use your ONAG with your FR and the IF AFR Example 1 Reducer Celestron 0 63x DFR 87mm and h 0 63x Guider Orion StarShoot autoguider GBF 15mm qarr 87 0 63 102 87 0 634 102 58 7mm X 58 7 15 43 7mm From th
21. e a ghost image may not be much an issue since it is dimmed and offset from its source by about 3 mm In any case never place any NIR filter or any other filters blocking the NIR in front of the ONAG otherwise you will not have any image of any star on your guider camera Focal reducers Focal reducers FR can be used with the ONAG Those reducers should be located at a specific distance DFR from the imager focal plane please refer to your reducer specification and user manual There are two options available You can place the FR in front of the ONAG at the SP if your TOBF associated with your set up matched the FR required back focus Most popular 0 63x focal reducer correctors such as Meade or Celestron can be used in a range of 1 25mm to their nominal DFR values without any significant alternation of their correction performances However the actual reduction factor h is a function of the distance q from the focuser to the imager focal plane If q is different from its nominal DFR value so h In first approximation we have h 1 q f and gq f 1 h Where f is the reducer effective focal length For instance the Celestron 0 63x corrector reducer has a focal of 235mm therefore its nominal DFR value 1s DFR o 63x 235 1 0 63 87mm or 3 42 If placed one inch further away from the imager focal plane its reduction factor h becomes Q 1 DFRo0 63x 25 4 112 4mm ONAG User Manual rev 5 1 15 2011
22. e table above we have two options adding a 8mm or a 16mm T threaded tube Example 2 Reducer Starizona SCT corrector 0 75x DFR 90mm and h 0 75x Guider SBIG Remote guider head GBF 17 5mm qarr 90 0 75 102 90 0 754 102 55 1mm X 55 1 17 5 37 6mm ONAG User Manual rev 5 1 21 2011 Innovations Foresight LLC From the table above we need to add a 8mm T threaded extension tube to reach focus with our guider and the Starizona FR attached to the imager Removing the GF drawtube use of a 114 nosepiece If you own a ONAG SC or new XT with a guider helical focuser please see section 11 below Use a 1 4 nosepiece instead of the GF drawtube first you will need to remove the drawtube For the ONAG SCT refers to the section 10 below There are two 6 32 nylon screws on each side of the focuser compression ring Those screws slide in two key slots or groves stopping the drawtube for leaving the focuser compression ring Remove and save the two screws now slide the drawtube away and then place your 1 2 nosepiece instead You can use the compression ring to lock it at the desired position However remember there is nothing stopping the nosepiece and your guider camera from falling anymore if the compressing ring screw is not tightened Be careful Innovations Foresight cannot be held responsible for the consequence of such an accident This ONAG GF mode of use is provided for convenience only and it i
23. eavy duty compressing ring to insure a 360 degrees grip on the drawtube This design eliminates any flexure Since the drawtube is 1 4 in diameter and can be removed this allows the use of any standard 114 accessories Very handy if your guide camera nosepiece does not come off In such configuration you may need an extra 1 4 extension tube to reach focus see section 7 The ONAG SC features a new helical focuser see section 10 for further information 6 A X Y stage XYS The XYS allows easy and quick search for a suitable guide star It is attached to the ONAG body on one end while it supports the guider focuser on the other end The XYS slides in both directions X Y axis using two stainless steel shafts each axis can be secured with 4 nylon screws two screws and two thumbscrews when you have settled on your guide star For convenience the screws can be tightened to provide any level of friction and comfort while moving the stage In normal operation only the two nylon thumbscrews for each axis need to be touched The other 2 slotted nylon screws are tighten only once using a screwdriver to insure proper smooth motion and remove any play Do not over tighten them 7 A collection of T threaded M42 x 0 75 extension tubes are available from Innovations Foresight They can be used with any of the standard and SC ONAG optical ports SP IP and GP or at the ONAG XT GP There are also three dovetail extension tubes
24. focus point is achieved when both ellipsoid collapse becoming a spot or a little tight cross This is normal and not a source of concern This feature becomes handy when manually seeking for best focus and it is used indeed by our real time autofocus technology SharpLock SL The ONAG XT has an integrated corrective optics and therefore does not exhibit such effect the guide star is round and seeing limited However the XT guider drawtube can be rotated to create some astigmatism for using SL This corrector is not available with the helical focuser versions Since most scopes and optical components are not optimized for the near infrared NIR there is maybe small distortion involved anyway Autoguider algorithms are mainly based on centroid algorithms and are not sensitive to this They average pixels from the all guide star area so the maximum pixel value or FWHM are not much relevant in this case unlike for imaging If you use computer assisted focusing software such has Maxim DL the right figure of merit should be the half flux diameter HFD or 42 FD The half flux diameter is the diameter in pixels that contains half the energy in a star image In other words if you add up the pixel values less the background inside the diameter and outside the diameter you will get the same number This measurement gives a very similar answer to FWHM but it is much more robust in the presence of seeing noise and can handle non circular distorted
25. focuser ring to the best focus position again 10 ONAG specifics The ONAG SC has pestilential the same specifications than the standard ONAG It has been designed for ASP C chips up to 28mm in diagonal ONAG SC unit ONAG User Manual rev 5 1 33 2011 Innovations Foresight LLC The ONAG SC X Y stage is based on a dovetail system there is no stainless steel shaft anymore This design insures a very rigid and compact stage It supports a new helical focuser for the guider at the GP The stage operation is identical than for the XT and standard version of the ONAG The helical focuser provides a smooth fine focus capability for the guider Each turn 360 degrees move the focuser by 400 microns 0 4mm Focuser locking a ON Focus ring ONAG SC helical guider focuser For focusing unlock the focuser locking screw and just rotate the focus ring in either directions until you have reached focus with the guider one turn is 400 microns 0 4mm Then hand tight the focuser locking screw please do not over tight it nor use any tool to do so you may damage your helical focuser otherwise This should give you a good enough rigid focus position for most setups and guiders However you can continue to rotate the focus ring by hand in the Same direction while the focuser screw 1s lock to secure even more the focus position This maybe useful for heavy guiding cameras However doing so will change a bit your
26. gs most likely but the reward will be huge in term of image quality Should you need more support or advise please feel free to contact us we will be glad to help ONAG User Manual rev 5 1 29 2011 Innovations Foresight LLC 9 ONAG XT specific This section describes the ONAG XT specific features and procedures Please read the above sections carefully first There are two version of the ONAG XT one with a drawtube focuser the other new with a helical focuser see at the end of this chapter about how to use this helical focuser Below on the left an image of the ONAG XT with a drawtube focuser on the right the ONAG XT with a helical focuser ONAG XT with drawtube focuser ONAG XT with helical focuser Innovations Foresight offers M42 x 0 75mm T mount spacers 8mm and 16mm long and male female dovetail 59mm spacers 8mm 16mm and 24mm long There are also female and male adapters for 2 and STC connections the 2 female adapter has a stainless steel thumbscrew for the compression ring full body Although the compressing ring provides a very rigid connection accident may happen and it is a good practice to have this back system to lock in place your equipment This female adapter has a 30mm depth which is more than enough for most nosepieces Be carefully not to exceed this length otherwise you may touch and damage the dichotic mirror Innovations Foresight would not be responsible for product any ONAG and assoc
27. h a FR you have to focus your scope at a plane behind the FR located at the distance p from the FR This is also the distance you need to consider for the guider since in this configuration FR is not part of its optical path For instance with a Celestron 0 63x focal reducer f 235mm DFR 87mm p should be p 87 0 63 138mm It is worth to mention that the calculation of the effective focal reduction factor h is more complex with a SCT since those scopes require moving the principal mirror forward which in return changes the scope effective focal length f For most SCT the focal length increases roughly 3 to 4 times faster than the back focus Let s use an average value of 3 5 times The nominal SCT focal length fnominai 1s reached around 100mm 4 of back focus from the visual back This allows for a star diagonal and eye piece room For instance with a C11 at f 10 we have frominar 2800mm Therefore if we use a Celestron 0 63x FR in front of the ONAG in low profile mode the effective focal f becomes p 138mm ONAG back focus 66mm fo 63x 28004 3 5 138 66 100 3 164mm And the resulting effective reduction factor h is h 0 63 3164 2800 0 71x ONAG User Manual rev 5 1 17 2011 Innovations Foresight LLC About 13 larger which means a reduced focal length of 1993mm instead of 1764mm You effectively use this C11 at f 7 1 The Celestron FR 0 63x or other ones for that matter will still correct for the SCT field c
28. h atmospheric turbulence seeing effect on the guide star star wander and distortion providing a better tracking and SNR The seeing effect in term of FWHM and HED scales as the 6 5 power of the wavelength therefore there ONAG User Manual rev 5 1 1 2011 Innovations Foresight LLC is up to about 70 seeing reduction when using the ONAG for auto guiding depending of you scope aperture local seeing and exposure time Our patent pending real time auto focus technology SharpLock SL keeps your imager at best focus all the time without any need of any imaging interruption for periodic refocusing SL works with all models of the ONAG for further information on SL please visit us at http www sbdcdev com ifi education real time auto focus sharplock This document describes the standard SC and XT versions of the ONAG Most of the functions and concepts are the same and therefore are presented for the standard ONAG Specific information for the SC and the XT versions can be found at the end of this document in the sections 9 and 10 Description The ONAG is composed of 7 fundamental elements 1 A fully multicoated dichroic beam splitter DBS or cold mirror The DBS reflects typically more than 98 of the visible light from 370nm to 750nm toward your imager More than 90 of the near infrared NIR portion of the light from 750nm to 1200nm goes through the DBS to be used by your guiding camera Because the
29. he new ONAG XT is equipped as the ONAG SC of a guider helical focuser at the GP The image below shows the ONAG XT helical focuser Focuser locking screw Focus ring ONAG XT guider helical focuser The helical focuser provides a smooth fine focus capability for the guider Each turn 360 degrees move the focuser by 400 microns 0 4mm ONAG User Manual rev 5 1 32 2011 Innovations Foresight LLC For focusing unlock the focuser locking screw and just rotate the focus ring in either directions until you have reached focus with the guider one turn is 400 microns 0 4mm Then hand tight the focuser locking screw please do not over tight it nor use any tool to do so you may damage your helical focuser otherwise This should give you a good enough rigid focus position for most setups and guiders However you can continue to rotate the focus ring by hand in the Same direction while the focuser screw 1s lock to secure even more the focus position This maybe useful for heavy guiding cameras However doing so will change a bit your initial focus position Therefore in this context the best procedure calls for recording how much you could rotate further from the best focus after you tighten the focuser locking screw then back off to the best focus position Now unlock the focuser locking screw and continue to back off the focus ring by the recorded amount above Finlay lock the focuser locking screw and rotate the
30. iated accessories and equipment damages due to failure to follow proper procedures recommended care and good practice The ONAG XT uses a 59mm dovetail system for the IP and SP This insures a rigid squared and secure connection as well as provides minimum back focus solutions Each female dovetail is equipped with three 4 40 UNC stainless steel set screws They must all be tightening to insure a secure attachment using a 0 05 Allen hex key wrench one is provided with the ONAG XT The set ONAG User Manual rev 5 1 30 2011 Innovations Foresight LLC screw tips have an oval shape to insure a good grip and to protect the aluminum surface of the male dovetail part Only limited force is needed to lock in position the dovetails please do not over tighten the set screws We do recommend that you use the long side of the Allen wrench as shown in the image below resist using the short side which may lead to excessive torque Allen wrench recommended procedure to use with the dovetail set screws The two images below show the location of the set screws on the ONAG XT body Accessing the third dovetail IP set screw requires moving down the X Y stage toward the negative direction of its Y axis ONAG User Manual rev 5 1 31 2011 Innovations Foresight LLC Three set screws 4 40 please tighten all Three set screws 4 40 please tighten all ONAG XT IP set screw locations ONAG XT SP set screw locations T
31. ing your usual auto guiding hardware and software If you are not using an automatic tracking calibration procedure you do not have to be concerned by the inversion effect of the dichroic mirror in your manual entry The guider uses the light coming straight through the DBS there is no reflection involved here The recommended focusing procedure assuming you have the right extension tube set up see section 3 above is as follow ONAG User Manual rev 5 1 12 2011 Innovations Foresight LLC Center the XYS and gently tight the nylon screws to insure an easy slide of any axis in any direction when displaced by hand while the stage does not move under its own weight Tighten the GF stainless steel focuser screw just enough allowing a smooth travel of the drawtube with a minimum of play see section 10 below for the ONAG SC helical focuser Select a bright star near your target do not over expose or the zenith and center it on the imager Then focus the imager using the scope focusing mechanism as usual Using the XYS center the same star and focus it using the GF tighten by hand the GF screw never use a tool If you cannot do so you may have to reconsider your extension tube selection When you move the ONAG guider focuser drawtube all the way the guide star should change form from a vertical ellipsoidal shape to a horizontal ellipsoidal shape or the opposite in function of your CCD reference frame position The optimal
32. nce Example 1 ONAG User Manual rev 5 1 9 2011 Innovations Foresight LLC Imager SBIG ST 4000 XCM IBF 23 mm back focus Guider SBIG Remote guider head GBF 17 53 mm back focus Differential back focus DBF 23 17 53 5 47 mm The closet DBF option from the table above is 8 mm of DBF This means either a 24 mm extension tube on the IP with a 8 mm extension tube on the GP IPBF 90 mm or a 16 mm extension tube on the IP with no extension on the GP IPBF 82 mm This gives us two possible values of TOBF a IPBF 90 mm TOBF 90 23 113 mm 4 45 b IPBF 82 mm TOBF 82 23 105 mm 4 13 Option b will provide the smallest optical back focus If used with a Celestron EdgeHD 8 SCT without any other accessory in the optical train you may want to use option a and add the 16 mm extension tube between the SP and the provided low profile SCT adapter 7 5 mm back focus This will place the imager focal plane at 113 164 7 5 136 5 mm Only 3 15 mm 1 8 too far This is close enough Example 2 Imager DSLR Canon EOS EF and EF S mounts Flange back focus distance 44 mm T ring adapter for EF EF S mount back focus 8 mm ONAG User Manual rev 5 1 10 2011 Innovations Foresight LLC IBF 44 8 52 mm back focus Guider ORION StarShoot autoguider GBF 15 mm back focus Differential back focus DBF 52 15 37 mm The DBF closest option from the table is 40 mm
33. ressing ring outside perimeter to stop it for moving away Those screws should be checked on a regular basis and each time a guider camera 1s attached They should be in place good condition and screwed deep enough to secure the drawtube while allowing it to move freely for focusing Check by moving the drawtube gently back and forth and verifying it cannot leave the focuser ring The maximum drawtube travel is about 9mm The guider focuser screw see section 6 as well as the X Y stage eight nylon screws should always be tight before using the ONAG for an astrophotography session moving the telescope or slewing its mount Failure to do so may result in significant damage due to the abrupt part and camera motions or falls The 4 nylon thumbscrews of the X Y stage as well as guider focuser screw stainless steel should be tightened by hand never use a tool such as a screwdriver Use only a screwdriver for the 4 slotted nylon screws when doing initial adjustment Please do not over tighten them We also recommend as good practice that each camera has a backup mean to stop it for falling should the primary mechanical interface fails for any reason A string could be used for this see what your camera user guide may suggest Should you need to clean the DBS first remove any dust using optical grade compressed air or brush Do gently to avoid scratching the DBS coatings If necessary and only if you could use a cleaning product for m
34. rs such as http www scopestuff com ss_tadpt htm ONAG User Manual rev 5 1 35 2011 Innovations Foresight LLC 12 Specifications no extension tube or adapter attached 13 In between for XT version Over all dimensions ONAG weight Imager back focus Guider back focus half way extended X Y stage full X travel X Y stage full Y travel excepted low profile X Y stage maximum off axis offset X Y stage maximum exploration circle Low profile SCT adapter thread Low profile SCT adapter ring inner depth Low profile SCT adapter back focus 2 tube adapter outside length 2 tube adapter back focus Guider focuser type Guider focuser travel Scope port Imager port Guider port T threaded tubes outside T threaded dovetail tube useful lengths Dichroic beam splitter coating Dichroic beam splitter protection both sides Dichroic beam splitter reflection visible Dichroic beam splitter visible range Dichroic beam splitter transmission NIR Dichroic beam splitter NIR range Anodizing Warnings maintenance and care 123 x 92 110 x 83 70 mm 770 800 g 66 68 mm 92 92 96 with helical focuser MM 37 mm 28 24 mm 23 22 mm 46 44 mm 2 24 tpi 12 5 mm male 11 female 8 7 5 mm male 2 female 4 30 mm 0 mm male 2 female 30 Compression ring 9 mm T thread M42 dovetail T thread M42 dovetail T thread M42 Fully knurled 8 16 24 mm
35. s IP Imager port IPBF Imager port back focus IXT Imager extension tube NIR Near infrared ONAG On axis guider SCT Schmidt Cassegrain telescope SL SharpLock real time autofocus SP Scope port TOBF Total optical back focus XYS X Y stage ONAG User Manual rev 5 1 40 2011 Innovations Foresight LLC 17 Notes ONAG User Manual rev 5 1 4 2011 Innovations Foresight LLC
36. s hand tight the ONAG focuser screw stainless steel to avoid any motion or flexure Now you are ready to come back to your target Center and fine focus it on the imager Then it is time to locate and center your guide star on the guider camera using the XYS If necessary adjust the guider focus with the GF Now tighten by hand all 4 nylon thumbscrews to avoid any flexure never use a tool Proceed with your imaging session Should you keep your cameras attached to the ONAG for the next session there is no need to focus the guider again 1f you did not touch the GF You will just need to focus the imager and use the XYS to locate the guide star which will be automatically on focus saving time Although if the DBS has a high efficiency broad band antireflection AR coating on its back if you overexpose bright star s you may experience dimmed ghost images of them offset by few hundred pixels unless your imager has a near infrared NIR cutting filter Most if not all one shot color cameras and DSLR have UV NIR ONAG User Manual rev 5 1 14 2011 Innovations Foresight LLC blocking filters Monochrome ones usually do not however the associated filters such as LRGB should take care of this cutting the NIR typically above 700 nm If not you may have to consider adding a UV NIR filter in front of the imager Alternatively should you want to image in NIR avoid overexposing your target For scientific and research purpos
37. s the sole responsibility of the user to take the necessary precautions Focuser drawtube Focuser ring 6 32 threaded hole for nylon screw Bone ne a Focuser screw XY stage and guider focuser top view ONAG User Manual rev 5 1 22 2011 Innovations Foresight LLC Focuser screw Focuser drawtube Focuser ring threaded hole for nylon screw XY stage and guider focuser bottom view Note that in such configuration T treaded extension tubes are not an option anymore and you will have to use 1 4 extension tubes if any instead Those are readily available from many sources When you put the drawtube back in place do not forget to replace the two nylon screws and to check that they will prevent the drawtube from falling The drawtube comes lubricated with grease for easy tube travel Should You have to add some use just a bit of grease to avoid any spillage on the DBS and ONAG inside body Grease for aluminum alloys with a large temperature range is recommended Never use oil 6 Low profile SCT adapter The provided low profile SCT adapter allows the ONAG to be attached to a standard SCT male thread 2 24 tpi with a minimum of back focus 7 5 mm about 1 3 The adapter comes mounted with Phillips stainless steel screws to secure the SCT female ring with the T thread core First screw the adapter to the ONAG SP or any T threaded accessories mounted in front of the ONAG su
38. stem for the XT version We provides standard offer such as a 2 nosepiece or a low profile female SCT adapter If you own an adaptive optic module such as the Orion SteadyStar or the Starlight Xpress SXV you can mount them directly between the SP and your ONAG User Manual rev 5 1 3 2011 Innovations Foresight LLC scope Use the ONAG for guiding and controlling the AO unit as well Since the off axis ports of both products are not used they should be covered to avoid parasitic light We offer an adapter plate for the SBIG AO8 adaptive optic module This allows you to mount the AO8 in front of the ONAG standard and SC versions Other adapter for any ONAG can be made by preciseparts www preciseparts com they have our products in file The SBIG AO L is only supported by the ONAG XT 3 An imager port IP The IP is used to attach the imager camera and related accessories such as a filter wheel to the standard and SC ONAG using a standard male T thread M42 x 0 75mm or a 59mm dovetail system for the XT version 4 A guider port GP The GP is used to attach the guider camera to the ONAG any version using a male T thread M42 x 0 75mm A low profile T threaded ring is provided to secure the camera at the desired position The GP 1s also the guider focuser drawtube see the element 5 below 5 A guider focuser GF The GF provides up to 9 mm of travel to adjust the guider focus The focuser uses a h
39. ues see your product specification or contact the relevant manufacturer or reseller With those two numbers compute the DBF and refer to the table The table here provides solutions with 8mm and 16mm spacers only However if you have your own spacers or want to use third party spacers you can reuse this information to find the best match just sum the recommended spacer lengths from the table to get the total spacer length required Alternatively you can also use the relations below to compute the necessary extension value at the guider port GP Positive values mean the guider must be moved away from the ONAG negative values the imager must be moved away from the ONAG ONAG User Manual rev 5 1 7 2011 Innovations Foresight LLC ONAG Standard and SC extension value DBF IXT 26 in mm ONAG XT extension value drawtube focuser DBF IXT 24 in mm ONAG XT extension value helical focuser DBF IXT 21 in mm Where IXT is the length of the imager extension tube spacer used in mm if any This spacer is placed between the ONAG IP and the imager or filter wheel IXT values lower than 16mm will reduce the upper Y axis travel of the XYS leading to a low profile configuration see 3 2 2 This equation assumes like the table that the guider focuser drawtube is extended half way 4 5mm IP Extension Tube s mm 2x16 2x8 2x16 8 16 2x8 16 8 16 8 16 8 None 16 None None None Non
40. ulti coating optical elements Never apply such product directly to the DBS surface instead use an optical grade soft tissue and gently clean the surface with the minimum of force and pressure as possible If needed the X Y stage shafts and guider focuser can be lubricated time to ONAG User Manual rev 5 1 37 2011 Innovations Foresight LLC 14 time with light aluminium and stainless steel compatible grease for extended temperature range Never use oil Use a minimum of grease and be sure it will not find its way inside the ONAG body nor spill on the DBS and cameras Never look at the sun or any bright sources or lasers with the ONAG from any optical ports Doing so could result in serious injuries Products performances specifications and features can be changed without warning Limited Warranty This Innovations Foresight IF on axis guider device ONAG is warranted against defects in materials or workmanship for a period of one year from the date of purchase This warranty is for the benefit of the original retail purchaser only During this warranty IF will repair or replace at IF s discretion any warranted device that proves to be defective provided it is returned postage paid to IF at 24 Ramblewood drive Glenmoore PA 19343 If the product is not registered proof of purchase such as a copy of the original invoice 1s required This warranty does not apply if in IF s judgment the instrument h
41. urvature as before with a slight change in h In short the FR does reduce the SCT focal length f and does retain any of its optical correction capability when applicable However due to the FR back focus f is larger than fnomina leading to a larger reduction factor h relative to Fionia ONAG User Manual rev 5 1 18 2011 Innovations Foresight LLC 4 Adjustable focal reducer AFR In order to minimize the resulting guider optical path associated with a FR in front of the imager ONAG IP IF offers an adjustable FR AFR for your guider The AFR works with almost any FRs as well as most guiders It has been optimized for NIR imaging using fully multi coated aspheric optics AFR adjustable FR for NIR The normal procedure with the AFR will be to place your imager FR directly at the ONAG IP You may need adaptors for your FR to interface with the ONAG T thread IP Locking screw AFR parts and nomenclature ONAG User Manual rev 5 1 19 2011 Innovations Foresight LLC Then place the AFR at the ONAG GP in one end and connect with your guider in the other end Now position the ONAG guider focuser half way out about 4mm this will give you some room for fine focus later Search for a bright star but do not over expose and place it at the center of the imager carefully focus your scope Center the ONAG X Y stage zeros on the yellow rulers For the next step you need to estimate the AFR extension valu
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