high speed photometer
Contents
1. comparison star sky background 25 3 mm to 51 4 mm 20 mm 2 mm 2 one for Ch1 Ch3 and other for Ch2 10 in Ch2 and 5 pairs in Ch1 Ch3 13 mm 2 one for Ch1 Ch3 and other for Ch2 10 in Ch2 and 5 pairs in Ch1 Ch3 0 4 to 8 0 mm see Tables 1a and 1b 40 mm 2 one for Ch1 Ch3 and other for Ch2 25x 8 mm 3 14 mm 34 mm 0 08 s 0 20 s Hamamatsu R470P S20 185 to 850nm UBVR and Vilnius photon counting 22 2 ns two one stage thermoelectric cool ers one for Chl Ch3 and other for Ch2 with actively ventilated air heat absorber two stabilized temperatures 5 C and 15 C which can be set according to the environmental temperature using GPS receiver 2us 5 ms per 12 hours 24 Technical specifications cont Communication between PC and interface Data transfer rate Minimal integration time Power supply requirements Dimensions of the photometer height max diameter including microscope max diameter of the main frame Distance from the mounting plane of the rotational bearing to the focal plane of the photometer Weight via RS232 port 19 2 kbd 20 ms 220 V 410 5 mm 210 5 mm 140 5 mm 200 mm 31 kg2. 20 APPENDIX 1 Position values In the next few tables it is explained what means the position number in the right indicator above the word POSITION on the handpaddle When the MOTOR value is 1 then POSITION number means that in front of the Chl and Ch3 are placed such a filters of the filter wheel A Table 1a Table 1a The positions and names of filters in filter wheel A of Ch1 Ch3 Position Filter in the wheel name U Johnson B Johnson Johnson Johnson for S20 m V V V Johnson for 520 R Cosins for S20 R Cosins for S20 U Johnson DOK Wb When the MOTOR value is 2 then POSITION number means that in front of the Chl and are placed such a filters of the filter wheel B Table 1b Table 1b The positions and names of filters UBVR filter set in filter wheel B of Ch2 Position Filter in the wheel name 1 U Johnson 2 3 B Johnson 4 iy 5 V Johnson for S20 6 Cosins for 20 8 9 10 When the MOTOR value is 3 then POSITION number means that in front of the Chl and are placed apertures of such a size Table 2a 21 Table 2a Positions and diameters of apertures in aper ture wheel A of Ch1 Ch3 Position Diameter Diameter in arcunits in the wheel mm 1 65 m Moletai tel 1 8 0 1 4 2 1 6 16 8 3 1 6 16 8 4 1 1 11 5 5 1 1 11 5 6 0 8 8 4 7 0 8 8 4
3. 8 0 6 6 3 9 0 6 6 3 10 Standard Light Source When the MOTOR value is 4 then POSITION number means that in front of the Ch2 are placed apertures of such a size Table 2b Table 2b Positions and diameters of apertures in aper ture wheel B of Ch2 Position Diameter Diameter in arcunits in the wheel in mm 1 65 m Mol tai tel 1 8 00 1 4 2 6 50 1 1 3 3 25 34 1 4 2 25 23 6 5 1 60 16 8 6 1 10 11 5 7 0 80 8 4 8 0 60 6 3 9 0 40 4 2 10 Standard Light Source When the MOTOR value is 5 then POSITION number 1 means that the prism in the Ch1 3 microscope M1 3 in Fig 6 is positioned so that in its ocular may be observed the Chl aperture picture the target star POSITION number 2 means that the prism in the same Ch1 3 micro scope M1 3 in Fig 6 is positioned so that in its ocular may be observed the Ch3 aperture picture the sky background Chl Ch2 Ch3 SH2 HV1 HV2 HV3 A1 A2 A3 S1 S2 S3 CL FM D CL1 3 CL2 M2P APPENDIX 2 Abbreviations and markings in the pictures First Channel Second channel Third channel Rotator fixator Rotator limb Rotator fine movement handle Field lens the main viewfinder Field lens raw positioning Field lens fine positioning Field lens position ruler Field lens position pointer Ch2 angular position limb Ch2 limb pointer Ch2 limb rotation stopper Ch2 angular positioning handle Aperture microscope for Ch1 and
4. OK button After these actions photometer is alive all systems and illuminations are working If something would went wrong in time of initialization then Photome ter Link Unlink would return the system to the starting point and initialization may be restarted 3 3 Positioning of the Ch1 and Ch2 stars and checking the Ch3 ACTION 1 Set the field mirror FM in Fig 4 of the photometer to IN position After that all star beams in the field are reflected 90 and may be watched via the main viewfinder FL in Figs 1 4 7 which can be re located in the field in two ways linearly with the Field Lens Position handle FLP and circularly rotating all photometer around the optical axis of the telescope when the stop handle of the rotator RF is released ACTION 2 After the telescope is pointed to the program star Ch1 star its image must be centered in the viewfinder FL in Figs 1 4 7 But before that the ruler pointer RP at the viewfinder croshair po sition ruler R1 must be set to the 0 value that means that the center 10 Fig 4 The top part of the photometer the Field Mirror Handle side of the viewfinder field and its croshair is pointed to the optical axis of the telescope and if the field mirror FM would be OUT the star im age would be on its way to the Chl aperture If the croshair is badly or too much illuminated there is potentiometer CL Fig 4 to adjust it It is good idea at the
5. of the HSTCP optical design area which may be searched moving the main viewfinder radially from 26 mm position till the 50 mm position of the ruler R1 this path is marked with thick arrow A in Fig 1 and the same time rotating all photometer around its opti cal axis using above mentioned rotator And Ch2 optical axis can be positioned on the selected star beam rotating all Ch2 housing around its 12 mm offset axis to the same value on its limb as pointer RP showed on the main viewfinder ruler R1 This possibility is showed with thick arrow B in Fig 1 But Ch3 the sky background channel is hard positioned in the same hous ing together with the Chl Because their distance is not changeable after Ch1 and Ch2 positions are fixed Ch3 is looking to some accidental area of the sky which may be with some contamination To make possible to escape from some problematic place it is made possible rotate a bit all Ch1 3 around the Ch1 optical axis the same time deviating from the previous area and se lecting some more acceptable Ch3 position this feature is demonstrated with the arrow C in Fig 1 The box of the electronics could be seen at the left side of the Fig 4 marked PB in Fig 4 It contains all electric circuitry necessary for the power supply to all units of the photometer for their control and for the data acquisition It includes microprocessor and computer interface step motor drivers electronics of cooling syst
6. ASTRONOMICAL OBSERVATORY OF VILNIUS UNIVERSITY HIGH SPED THREE CHANNEL PHOTOMETER HSTCP USER S GUIDE To Mol tai version EN N 2 fol E Earth vae Edited by E G Meistas Vilnius 2002 TABLE OF CONTENTS PART A PHOTOMETER DESCRIPTION I INTRODUGCIION ee Eyre ter nme ei hives ERES 3 2 SHORT INTRODUCING TO THE PHOTOMETER 3 PART USER S MANUAL 3 BEFORE THE OBSERVATIONS ssssssssssss ee 8 3 0 Controlling the instrumentation 8 3 1 Starting the 8 3 2 InitialiZati On on decet pog Rebel er da bsc Baer ead 9 3 3 Positioning of the Chl and Ch2 stars and checking the 8 3 4 Setting apertures centering Ch1 and Ch2 stars checking Ch3 11 3 5 Continuing Auriga program settings and data recording 15 4 AT THE OBSERVATIONS sssssssssssssss sss nnn 16 4 1 Continuous time series observations of the variable 17 5 AT THE END OF 18 6 e eee e e 18 APPENDIX 1 Position 1 20 APPENDIX 2 Abbreviations and markings in the pictures 22 APPENDIX 3 Technical specifications of HSTCP 23 PART A PHOTOMETER DESCRIPTION 1 INTRODUCTION General purpose high speed three
7. Ch3 Aperture microscope for Ch2 Ch1 and Ch3 shutter Ch2 shutter Chi Ch2 High voltage inputs Chi Ch2 amplifiers Chi Ch2 Ch3 signal outputs inputs Field lens croshair illumination regulator Field mirror IN OUT handle Ch3 slight deviation knob Ch1 Ch3 aperture illumination regulator Ch2 aperture illumination regulator Ch2 microscope prism IN OUT handle High Speed Three Channel Photometer High Voltage output photomultiplier Tube Standard Source names of passbands of Johnson s photometric system 23 APPENDIX 3 Technical specifications of the HSTCP Number of channels Distance between Ch1 and Ch2 Distance between Chl and Possible deviation of the Ch3 Number of filter wheels Number of filters in each filter wheel Diameter of filters Number of aperture wheels Number of apertures in each wheel Diameters of apertures Diameter of field eyepiece Number of aperture microscopes Magnification of microscopes Diameter of the field of microscopes Number of Fabry lenses Diameter of Fabry lenses Focal length of Fabry lenses Time of the filter wheel turn to the neighboring position over 5 positions Photomultiplier type spectral range Photometric systems Detection mode Dead time of photon counters PMTs cooling system Temperature of the PMTs Time synchronization system accuracy of absolute timing Maintenance of accuracy using only inner oscillator 3 Chl target star Ch2
8. ar light in each channel unit is transformed into parallel light beam which passes filters placed in two filter wheels and at the end as the images of the primary mirror are projected onto the photocathodes of the photomultiplier of the each channel PART B USER S MANUAL 3 BEFORE THE OBSERVATIONS 3 0 Controlling the instrumentation It is recommended that the dark counts in all three channels as well as light counts from standard sources would be checked before observations The sense of this checking is that observer must be sure that dark counts and sensitivity of the channels are the same or similar to the ones received in previous days If the large difference in those values are observed the reason of those differences must be found and fixed Test of long time several hours stability of both dark and light signals should be measured especially after instrument was not used for some time after transportation in hard conditions etc 3 1 Starting the system First of all it must be checked whether both shutters of Ch1 3 and Ch2 SH1 and SH2 in Fig 8 are closed At the first exercises when studying the photometer The Low Voltage 24 V in Fig 4 power must be ON but High Voltage in Fig 4 must be OFF On the contrary at the normal observations High Voltage HV stays ON all the time day and night usually In that case the handling of the photometer must be especially careful looking that the photom
9. beginning of the observations to adjust the tele scope guider so that when the star image is on its croshair it is close to the viewfinder center too This action saves lots of time at the future observations ACTION 3 When the program Ch1 star is centered the next step is to locate and set the comparison Ch2 star It could be done when observer is searching the suitable star manually rotating the handle FLP in Figs 2 4 7 and the same time rotating all photometer around the optical axis of the telescope The stop handle of the rotator RF must be released at that But if precalculated values of ruler R1 and rotator limb RL are available then much less time is necessary to set the viewfinder to the Ch2 star ACTION 4 Ch2 star setting After action 3 the Ch2 star is on the crosshair of the main field viewfinder but not on its way to the Ch2 of the photometer if the field mirror FM would be switched to OFF To make the final setting one must read the value of the viewfinder ruler R1 scale at the ruler pointer RP and releasing the stopper L1F rotate the handle of the Ch2 unit position L1H till the limb L1 pointer LP will point to exactly the same 11 Fig 5 The top part of the photometer the Viewfinder side value as it was read on the ruler R1 After this action the Chl and Ch2 stars are set into their positions and it is time to go to the next step to set center the images of the stars into appropriate apertu
10. channel photometer HSTCP is designed for the time series photometry of variable stars as well as for the multicolor photometry using UBVR and Vilnius photometric systems Other photometric systems as Stromgren or others could be used in the photometer The pho tometer conforms to main requirements of observations according to Whole Earth Telescope program as well as to ones of the photometry of variable stars as well as according to usual observational programs of multicolor photometry Abbreviations and markings used in the pictures are given at the end of the paper in the Appendix 2 and technical data of the HSTCP in Appendix 3 This photometer and the software was made at Vilnius University in Laboratory of astrophotometry of Astronomical Observatory in fruitful collaboration with people from Institute of Theoretical physics and Astronomy R Kalytis was the project manager R Skipitis the main designer of mechanical and optical parts and many parts were machined by him too E Siauci nas developed main electronics and R Janulis created the software 2 SHORT INTRODUCING TO THE PHOTOMETER The photometer HSTCP consists of five main parts 1 optical mechanical module 2 box of electronics 3 24 V power supply 4 manual control hand paddle and 5 GPS receiver There are only few functions possible to access before the special software AURIGA or CORVUS are activated Most of the adjustments are possible to make with the step m
11. data numbers starts to show up in the upper left main panel window and the data points in the lower window of it If the Ch1 3 and Ch2 shutters are still closed these numbers and point positions must be quite low the dark counts To start recording data of stars open them SH1 and SH2 in Fig 7 4 1 Continuous time series observations of the variable star should be executed in the following order Darks 1 Recording of the dark counts in all three channels at the closed shutters of both channel units SH1 Sh2 in Fig 7 Must be recorded about 10 points Sky 1 First recording of the sky background in all three channels Shutters open but stars moved 5 aperture sizes away The best is to control this offset in the autoguiders monitor where the size of the aperture is marked Must be recorded about 10 points too It is good idea to check if there were no changes in the background Ch3 data when images of stars were moving it gives some understanding if there is good place for the background selected 17 18 Stars Sky 2 Darks 2 Stop Observations return stars to the centers of their apertures and do record ing of the data of the target star in Chl comparison star Ch2 and sky background in Ch3 Every problem with the sky or the instrumentation must be written in the log file Final recording of the sky background in all three channels Star images must be moved approximately to the same place
12. e Com bining this movement and rotation of all photometer around the optical axis of the telescope it is possible to survey the sky field around the target star the first channel and to select a comparison star for the second channel in a ring shape field accessible for the Ch2 unit When the flip mirror is withdrawn the light beams of all three channels is directed to the diaphragm wheels The focal plane of the telescope lies at the plane of two motorized diaphragm wheels from which a field from 0 4 to 8 0 mm can be selected Though there are three channels in the photometer but there Fig 2 The main picture of the photometer are two diaphragm wheels only The first one contains apertures placed in pairs for both Chl and because these channel units are too close to each other to have two separate wheels and for the movable Ch2 the second separate diaphragm wheel is used After passing the apertures the light beams of the stars are directed to the Fabry lenses of the channel units if the prism of the aperture microscope M1 3 is not inserted When the prism is IN the star light is directed to the aperture microscope For the Chl and one motorized movable prism is used It could be set in three positions Chl Ch3 and withdrawn When the star is centered in the selected aperture above mentioned prism is moved to the OUT position and the star light beam passes to Fabry lens After the Fabry lens st
13. e for observations with 1 65m Mol tai telescope Motor 3 Position 2 Center the target star in this aperture too Checking Ch3 if there is good clean background Set Ch1 3 microscope prism to see the Ch3 field Motor 5 Position 72 Looking to the microscope ocular one must investigate whether there is no obvious star in the field The aperture there must be 1 6mm as it was left for Chl because apertures in this disc are made in twine pairs Aperture illumination can be adjusted with the same handle as for the Chl aperture CL1 3 If there is some obvious star it is possible to move Ch3 slightly to the neighboring position rotating the special deviation knob D in Fig 6 But this background checking is only the starting measure The final checking must be done at the observations moving the telescope slightly around the region and looking to the data whether there is no obvious changes in Ch3 readings Do not forget to withdraw the prism from the light path Motor 5 Position 0 Centering the comparison star in Ch2 This channel has no motorized prism in front of the aperture micro scope M2 It has the special handle M2P in Fig 6 in the housing which may be used to set beam deviation prism IN and OUT manually For the centering of Ch2 star this prism must be IN and the Ch2 aperture wheel must be set to the biggest 8mm aperture for the beginning on the handpaddle Motor 4 Position 1 If there was
14. em low and high voltage power supplies 24 V power supply is standard AC DC converter converting 22220 V to 24 V operating as a main power supply of the photometer In the pictures Figs 2 4 8 one can introduce to all controls of the pho tometer starting from the rotator bearing through the field lens the main viewfinder and aperture microscopes and finishing with the signal outputs at the amplifiers discriminators It is very important even at the first introduction already to locate the handles SH1 and SH2 shown in Fig 7 of the shutters on both Ch1 3 and Ch2 housings These shutters must be closed at all adjustments of the telescope and of the photometer units and must be opened only when the photometer is ready for the safe measurements The special attention must be paid to the three housings of the amplifiers discriminators of this photometer A1 A2 A3 They are most prominent and not too strong mechanically units and they may be damaged by the accidental banging even with the comparatively modest force There is separate handpaddle Fig 9 which may be used for the manual control of the photometer features when observer is at the telescope GPS receiver is the standard receiver of signals from the Global Positioning System GPS and is providing standard information coming from GPS includ ing one PPP pulse per second signals for synchronization of the photometer to the Universal Time UT In enlarged fla
15. nge close pictures of the photometer Figs 4 7 are shown more clearly above mentioned and some other important controls to be used at the observations They will be addressed when it will be needed in this user guide at the description of the observers actions at the positioning of the stars into the appropriate channels and at the observations The main measuring channel first channel Ch1 of the photometer is designed for the light measurement of a target star The second channel Ch2 is used for the light measurement of a comparison star and can be moved and positioned in the ring field around the first channel The third channel Ch3 is designated for the light measurement of the sky background and it is in one mechanical optical unit with the first channel It is located at the constant distance with the possibility of small rotational deviations from the first channel Light beams of all three channels can be observed with the large field eye piece unit FL the main viewfinder of the photometer All these beems are passing 130 mm diameter central hole of rotational bearing These light beams might directed either to this movable large field viewfinder when the big flip mirror FM is IN or to two diaphragm wheels to apertures of all three chan nels when the flip mirror is OUT Movable large field eyepiece could be moved linearly into any position till the distance of 50 mm perpendicularly to the main axis of the telescop
16. no mistake performing Action 4 the selected comparison star must be in the field Aperture illumination may be adjusted with the potentiometer CL2 Fig 6 After Step 1 Step 2 Step 3 Fig 10 The preferences set before the start of the observations moving it to the center of this big aperture the aperture wheel must be changed to the same size working aperture as it was set for the Ch1 3 to 1 6mm in our case To have this aperture in Ch2 too on the handpaddle must be Motor 4 Position 5 Table 2a in the Appendix 1 Do the final centering of the star in this aperture too Withdraw the prism from the Ch2 light path with M2P After this action photometer is ready for the time series photometry of the selected stars 3 5 Continuing Auriga program settings and data recording Program AURIGA preparation for the observations The next step in preparations is setting the preferences for the data record ing Click Photometer Preferences The panel of preferences pops down and one must fill in the data in it according the plans of observations Fig 10 Here must be set sizes of the work apertures for every channel and marked the holes of the 10 hole disk of the photometer where the filters for this observation were placed Even if observations were planned in the integral light through one hole this hole box must be marked and some name letter must be there Then system will know that the fil
17. of the campaign or to leave power ON is not safe for some reason then must be switched off the HV power and 24V power as the last step of the observations switches HV 24V in the Fig 4 1 6 RECOMMENDATIONS Sky maps with the useful field circles drawn on them should be prepared e g the field for finding of the accessible comparison star all field of the viewfinder eyepiece The photometer should be switched on high voltage and cooling selected for the season two or three hours before the observations It is necessary for stabilizing of the sensitivity of all detection channels The best case is if high voltage and cooling are not switched off for all run of observation all nights and days TT T7 PEELE 4 16 2001 1189408 ftugdsig rau 4 16 2081 206456 frig r au 4 17 2001 217357 tdark Paw 4 17 2001 T3319 tuge hanye 4 18 2001 124537 IPGI3d6h mRAU L J2 2z020801 4259146 4 21 2081 110809432 4 23 2001 S548533 271072881 lllz75 Fig 13 Auriga s window with the final savings of the data 3 Dark counts without cooling and with cooling should be checked every evening after switching the photometer ON before the start of obser vations and after the observations Comparing these values with the ones received in the previous days makes possible to control the system stabil ity 4 Tt is good idea to check the signal counts from standard sources SS in all channels periodically
18. otors via the handpaddle only which is active only when the software is loaded and initialization of the pho tometer is completed Optical mechanical module of the HSTCP contains all necessary optical and mechanical controls to find the target and the comparison stars to center their images in the apertures and to apply the light of both stars and of the sky background to the photocathodes of the appropriate photomultipliers PMTs The flange of the photometer attachment to the telescope contains very important mechanical device the rotational bearing with the position limb RL see this and the next features in Figs 2 4 6 It makes possible to use this photometer even with the telescopes which do not have their own positioning bearing The handle RH is for the fine rotation of the bearing and handle RF is to stop the bearing in the required position for the fine rotation with the RH or to release the bearing for free raw rotation by hand The main principle of the optical design is shown in the Fig 1 When tele scope is pointed to the target star and it is centered in the aperture photometer Optical axis is on the optical axis of the telescope To see this star in the main viewfinder FL in Figs 2 4 5 field center on its croshair this radially mov able viewfinder position pointer RP must be at 0 on the position ruler R1 see them in Fig 5 The comparison Ch2 star may be selected in the hatched Fig 1 The principle
19. r number could be set numbers from 1 to 5 in the indicator and after that when the right button POSITION is pressed with the same or buttons necessary position of the unit to which this engine is attached can be selected In Fig 9 are shown numbers of the step motors and the units which they are handling All meanings of the numbers in the indicator POSITION are Fig 7 The lower part of the photometer the Channel Units 13 14 CO 2 9 9 9 Filter Filter Disk of Disk of Pri rism wheel wheel apertures apertures Ch1 3 A B A B Fig 9 The motor numbers and units which they are controlling given in the tables at the end of this manual APPENDIX 1 Position values ACTION 5 ACTION 6 ACTION 7 The next actions assume that handpaddle is in active ON state Setting the Ch1 3 microscope M1 3 in Fig 6 prism for the cen tering of Chi the target star Set the handpaddle motor 5 and position 1 The deviating prism will reflect to the microscope small region around the optical axis of the telescope Set the biggest 8mm aperture Motor 3 Position 1 Looking to the microscope ocular the target star must be seen in the field If aperture perimeter is not enough or to much illuminated adjust it using the potentiometer CL1 3 Fig 6 Move image of the star to the approximate center of this all microscope field aperture Change to 1 6mm aperture the usual working apertur
20. res of Chl and Ch2 It is completed job from here with the field mirror IN From now it must be made OFF with the handle FM Fig 4 to let the beams of the stars to the apertures 3 4 Setting the apertures centering Ch1 and Ch2 stars in them and checking Ch3 Since the data acquisition program is working and photometer initialization is completed it is possible to continue setting of the photometer the aperture sizes centering stars into them and setting of the filters The next few actions must be performed manually via the handpaddle Fig 8 and the first step is to take control from the computer to the handpaddle to press button ON of it If interface is prepared to work with the handpaddle indicators at MOTOR and POSITION will show some numbers in their windows If interface is not ready for some reason e g it might be still busy with some measurements then both indicators will show dashes 12 Fig 8 The handpaddle for manual adjustments at the photometer In that case it is possible to force the interface to give priority to the handpaddle pressing OFF and few seconds later ON This will force interface to stop what it was doing and after some time which it might use e g to save the data of the activity and it will show some numbers in above mentioned indicators announcing that it is ready for the manual commands Then with the handpaddle buttons or the needed step moto
21. t upper corner of the main Auriga s panel changes into the happy one with the GPS letters in it After this procedure it is possible to adjust computers initial clock with the GPS system too click the PC button in the same panel for that All this process may be repeated if for some reasons the linkage failed but before that Tools GPS Link Unlink must be performed In the AURIGA s Notes file must be written all necessary information related to the recent observations It must contain the information about the site observatory the telescope the photometer observers weather conditions as well as the main technical information instrumentation operating modes values of high voltage cooling mode photomultipliers Software used etc 4 AT THE OBSERVATIONS If the above mentioned procedures are performed then it is time to check if the Chl and Ch2 stars are still in their apertures and centered use handpaddle again as it was explained above in actions 5 and 7 If High Voltage is not ON yet it is time to start it the switch HV on the Power Box PB in the Fig 4 n BBEBEEBBBERBH ia i e GET h aima GELEE T i Ecce 5556955 Fig 12 Auriga s window as it is at the data floats in To start data counting and recording click button GO in the main Auriga s panel under the menu bar Lines of
22. ter disk must stay still at this hole and data in the data file will be marked with this fake filter letter too Computer data and time should be checked to be the recent one If there are problems with the GPS system then it is possible to make photom etry counting on computers initial clock Actually the system accepted computer time after the linking and initialization procedure already And if computer time will be used it should have been set to the correct time as exactly as possible before the initialization 15 16 Fig Step 4 Step 5 11 Auriga s panel for the system linking to the GPS unit and the panel of the GPS preferences Much better timing may be reached if computer clock is synchronized with the GPS time signals This may be done from the AURIGA main window menu Tools submenu GPS Link The GPS Link window shows Port number IRQ number and communication speed They are set according the system requirements and are accepted as they are usually Clicking Link button starts the process of computer linking to the GPS unit When everything went smoothly message Port ready appears and after OK the panel of GPS preferences pops down In this panel observer can see the GPS data If data is acceptable and receiver sees enough not less than three satellites then button Interface finishes the linking process after 10s system gives the sound signal and the blue clock icon in the righ
23. ultipliers would not get too bright illumination they can be totally damaged Aperture wheels filter wheels and reflecting prisms of both microscopes are motorized equipped with the step motors five of them It is possible to handle them only via operational computer or via the handpaddle when the data acquisition program AURIGA for WET style time series observations or un mccmw n dc edu eds sd nj d EEE Fig 3 Auriga s starting panel and submenu Photometer CORVUS for multicolor observations is launched working properly and pho tometer is initialized Except that GPS unit must be launched too otherwise system will use computer initial time it is OK if exact time is not necessary e g at photometer investigations 3 2 Initialization After the AURIGA EXE is started all actions of photometer initialization in the opened window must be performed via the menu and submenu commands First click menu Photometer then submenu Link Fig 3 After the linear window is on check if everything the port number IRQ number and communication speed are correct init Then give the command to link computer to the photometer and initialize it clicking button Link If everything the cables and powering is correct then the progress bar appears and after it is filled in if everything went smoothly the software gives message READY in the window To accept and to finish initialization click
24. where they were at the first sky recording and about 10 data points must be recorded again Final recording of the dark counts in all three channels Close both shut ters SH1 and SH2 and record the final 10 points Stop data recording by clicking the same GO button at the top of the Auriga s main panel Actually this button has three functions the mentioned start and stop of the data recording But if after recording is stopped and GO would be clicked again observations would be continued with the recording of the data into the same binary file which was used before So button can perform the PAUSE function too making some gap in the recorded data The system records data into automatically made in file continuously after each integration and data does not disappear even at power failure It is even possible to continue data writing appending to the same file after new load and initialization of the system with menu commands File Restore and GO 5 AT THE END OF OBSERVATIONS The binary data file which was used for the data recording was named by the Auriga automatically with some letters and numbers It is good idea to re name it at the final saving to something more informative e g PG1336A RAW Dot hat with File Save As in the Auriga s main panel and make File xit to stop the Auriga The last action the power switches If it is the final observation
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