Calypso
Engineering Diary Index
During our engineering trips to the Calypso
Telescope we do our best to keep a record of our accomplishments. We also try
to include any data, which we feel is important and/or might be important for
future reference. If you have any questions, or if you would like more
information email the observatory at <mailto:info@calypso.org>
For a current list of the open action/service/maintenance items at Calypso please refer to the Calypso ToDo List
Summary
These trips primarily addressed the residual
servo error in the two main axes and alignment and initial debugging of the
adaptive system. We also spent a fair amount of time tracking down and
repairing lightning damage from the summer storms.
Summary
This was the first trip to get the adaptive
servo up and running. The bandwidth was poor but we were able to lock on a star
and get an image. There was a measurable reduction in the FWHM and the peak
intensity.
Summary
The primary purpose of this trip was to tune
the adaptive servo and work on the Farrand periodic error problem.
The last trip proved that the adaptive servo
worked, but the bandwidth was much lower than expected. During this trip we
discovered some software bugs which caused the notch filters in the servo
controller to filter at 1/(2*pi) of the correct frequency. Once we had fixed
the bugs and measured the plant response we were able to get the bandwidth up
to about 8 Hz. This is not too impressive, but the plant response data which we
obtained will allow us to develop a better set of servo coefficients which we
will implement on the next trip
We were able to determine the cause of the
Farrand periodic error. Frank had built and installed a circuit to introduce
controlled cross talk as suggested by Farrand. When this did not work, we took a
closer look at the frequency signals and began to suspect that the residual
error was actually part of the Farrand pattern. Discussions with Farrand
confirmed that this was indeed the case. Since this error is part of the
Farrand itself, it should be stable and we can remove it in the servo software.
Summary
There were two primary goals for this trip.
First, Alan Schier was provided the adaptive system plant response data from
the November trip and he is working on a new servo compensation scheme to
maximize the bandwidth. Alan came to the telescope to help implement his servo
system. Second, we wanted to test software to remove the Farrand periodic
error.
We were successful in reducing the main axis
encoder errors to 0.07 arc seconds rms in azimuth and 0.03 arc seconds in
elevation.
We eliminated the last of the bugs in the tertiary
software and we were able to tune the servo for a 30-40 Hz disturbance
rejection bandwidth. There appears to be some cross coupling in the axes which
is limiting our ability to achieve higher bandwidth at this time.
There is still a problem with the right
rotator as it travels through 6 degrees in a negative direction.
There were two trips in January, 2000. Don
Neill visited the observatory from January 10th to January 13th.
Don's goals were to update the Sun operating systems to the latest version of
Solaris, restructure the Sun network directory system and check for any Y2K
bugs. Don was assisted by Dawn for two evenings of observing.
The second trip with Bruce Truax and Frank
Scinicariello was from January 18th to January 23rd. The
goals for the second trip were to make the adaptive tertiary easier to use, fix
the rotator over speed problem, fix the problem with the rotator jumping out of
park at shutdown, complete testing of the filter changer and begin integration
of the WFCam shutter.
The primary purpose of this trip is to work
with Rene Racine on a telescope familiarization run. We also hope that Rene
will be able to provide us with some guidance to optimize the operation of the
tertiary servo system. Frank and Adeline will arrive at the telescope in
advance of Rene and Bruce. Their goal is to improve the telescope pointing
model so that it will be possible to take both longer unguided and guided
exposures.
The purpose of this trip is to work on
implementing some of the changes recommended by Rene Racine last month. In
particular, we want to close the tertiary servo/TOI/TCC feedback loop. We also
want to make sure that Adeline is trained on telescope operation so that she
can operate the telescope on her own.
There are three main goals for this trip:
1. Fine-tune the alignment of the adaptive
system detector so that it is well centered on the pick off mirror.
2. Improve the usability of the telescope so
to make it easier for Adeline and visiting astronomers to use.
3. Investigate the reason for the lower than
expected light efficiency and try to determine the root cause(s).
A more detailed to-do list is included in the
diary.
The goals for our June trip are detailed
below. The primary purpose of this trip is to reinstall the HRCam dewar with
the new, clean getter and verify that the CCD QE has improved. We also have the
new fiber optic for APD # 3 which should improve the overall efficiency of the
adaptive system significantly. If possible, we would also like to replace the
shutter with the new Uniblitz VS-45 but this is dependent on the fabrication of
a number of metal parts.
The main goal for this trip is to make the
switch to the new TCC running on the VAX Alpha. We will also try to bake out
the dewar and have it leak tested. In our spare time we will see if we can get
the WFCam guider to work.
This trip has three primary goals. The first
is to repair the leak in the HRCam dewar. The second is to complete the switch
to the new TCC by identifying the correct form for the pointing model. The
third goal is to optimize the tuning of the tertiary servo. In addition to
these three primary goals, we would also like to test the new guide camera on
the sky and install the gate valve and controller on the vacuum pump.
The primary goals of this trip are to prepare
for the arrival of the WFCam dewar by testing the Wfcam subsystems (i.e. Filter
Changer, Shutter, Guide Camera). In addition we also want to perform rigorous
tests of the serial communications between the Alpha and the Ziatech, work more
on tuning the tertiary servo, upgrade the TCC software to the latest revision
and perform a bench alignment of the trident optics.
We plan to remove the adaptive system trident
assembly and set it up on the optical bench in the utility shed and use a
microscope to help us adjust he position of the fibers. The unit will be
reinstalled on the telescope and we will test the light collection efficiency
and adjust the servo gain for optimum performance.
We are hoping that Frank will arrive at the
telescope on February 16th with our working WFCam dewar. If this happens we
plan to install the interface board into the jupiter workstation and test the
operation of the dewar. We would like to leave the dewar in working condition
(but probably not on the telescope) so that Don can work on the control
software.
We would also like to get the guide camera
working and tested.
In parallel with these tasks we will continue
to try to identify the cause of the random serial communications errors.
The purpose of this trip is to install the
WFCam on the telescope, test all systems and hopefully get the TOI integrated
with hardware so that the camera is fully functional (at least as fully
functional as it can be with only two of the 4 ccd's). In addition, we would
also like to develop an instrument model for the guide camera so that it can be
used for guiding and pointing model generation.
During the installation of the WFCam Bruce
plans to install more extensive baffling in the HRCam. This will involve
removal and disassembly of the HRCam.
The installation of the WFCam went very well
last month, but due to poor weather at the end of the trip we were unable to
test it on the sky. During this trip we plan to test the new instrument on the
sky and create instrument models for the main camera and the guide camera. In
addition, we want to create a number of different camera configuration files so
that we can use all 4 amplifiers simultaneously. We also plan to test the new
version of the TOI and possibly install the new TCC and Guide Camera Code.
While we did make progress last month getting
the WFCam to work, we were not able to complete our tasks, primarily due to the
failure of the instrument rotator D-A chip. Also, the development of the CCD
timing files went slower than expected due to poor documentation on the Leach
software and the need for Frank and Bruce to learn the DSP language and decipher
the file formats. (The hacker attack did not help either). Our goal this month
is to complete the integration of the WFCam. We plan to fine tune the timing
files for both CCD's and configured the camera to read out both CCD's
simultaneously. We will also complete the creation of the camera instrument
model and test out guiding and automated pointing model data acquisition.
In addition to all of the work on the camera,
we plan to install the first dewar auto fill station on our storage dewar. If
this works, we will order a second station so that we have one for each camera.
We will also meet with Gary Clemons to get him started on the fixturing
necessary to make pumping the WFCam dewar simpler.
The primary goal for this trip is to get the
WFCam guide camera working better so that we can start taking science images
with the WFCam. We also plan to update the TCC to the latest revision (2.5.4)
which includes a lower intensity guide star catalog so that we should be able
to collect pointing model data without inserting the ND filter.
Achieving these goals will require the
cooperation of mother nature. If she does not cooperate then we will work on
maintenance items and finish up the guide camera in September.
This is primarily a maintainance trip.
We will be checking the servo tuning, washing the primary mirror, installing
UPS batteries, cleaning the inside of the HRCam dewar, etc. In addition, we
also plan to work on the WFCam guider to get it ready for observations this
fall.
This is a repair trip. During the
observing run in September both the WFCam shutter and the HRCam filter changer
developed problems which could not be resolved by the observing staff. The
WFCam shutter web has become damaged and must be replaced. The HRCam filter changer
is jammed and it is not possible to change filters. In addition, both dewar
windows need to be cleaned due to condensation.
As with the November trip, this is
primarily a repair trip. We received the motors for the WFCam shutter in mid
December. Attempts to install them remotely resulted in some additional minor
problems which require a visit to resolve. In addition to repair of the shutter
and testing of WFCam the WFCam 5V power supply will be replaced and the filter
changer calibration will be carefully tested.
After Don's run in late
January, Elaine came to the telescope for a couple weeks of observing. She noticed that the WFCam CCD
temperature was high. She pumped
the dewar and was unable to keep the temperature low. We determined that there must be a leak. Elaine and Hal rebuilt the main dewar
valve but this did not solve the problem.
In addition, one of the two CCD's appears to be contaminated and we are
unable to get the QE up to reasonable levels. We assume that the entire inside of the dewar is probably
contaminated. The primary purpose
of this trip to completely disassemble and clean the WFCam dewar. The work will be done in Mike Lesser's
lab, hopefully with Mike's assistance so that he can check the QE. In addition it appears that the HRCam
filter changer needs a tune up.
The repairs to the WFCam dewar in February were incomplete because one of the CCD's continued to have low QE even after cleaning. We left the dewar at Mike Lesser's lab and he baked the ship in his oven for about a week and he was able to recover the QE. Mike reassembled the Dewar and sent it back up the mountain where it was installed by Hal. Adeline pumped the dewar and it held a good vacuum for about 3 weeks. Then suddenly in the middle of Elaine's run the dewar would not hold temperature for more than a few hours. It appears that the dewar has once again sprung a leak. The prime focus for this trip will be to identify the leak and repair it. Bruce will also represent Edgar at the Kitt Peak Tenants meeting on April 22nd at the NOAO offices in Tucson. There are also a number of additional relatively minor repair issues to be addressed.
There have been ongoing problems with the upper CCD in the WFCam. We have had a problem with low horizontal CTE and/or blooming and recently there have been exposures where the entire CCD is blank. One of our goals on this trip is to resolve both of these problems. We suspect that there may be two separate problems, an intermittent electrical connection and incorrect clock levels.
In addition to the CCD problems, we will also address a number of other periodic maintenance issues and install new software to address some known bugs.
The purpose of this trip is to replace the motherboard in the guide camera PC, investigate and try to resolve the cause of and intermittent problem causing the left rotator servo amplifier to become disabled and finally, attempt to get more evidence to identify the cause of the infamous 'bad reply' error.
There is also the possibility that an update to the TCC software will be ready for installation.
The purpose of this trip is to repair the WFCam shutter. The shutter was recently returned to Connecticut where Jim Soobitsky made some modifications to improve the reliability. When the shutter was returned it was tested in the electronics room using the test cable. The shutter was then reinstalled on the telescope and upon attempting to use it for the first time, many bad things happened. One of these bad things was a significant overheating of something on the shutter drive board. Hopefully it will be possible to fix the shutter and get the WFCam up and running.
If there is additional time, we will also check the alignment of the HRCam adaptive system, reset the secondary and perform a pointing model with the WFCam. Finally, we would like to verify that we have truly solved the Bad Reply communications error.
Wow its been a long time since my last trip! The telescope has been working so well that I have not had to visit Calypso to fix anything. We had one rather major problem over that last 4 months when our WFCam ion pump drilled a hole in its housing and we lost vacuum. After Elaine replaced the pump with a spare, the dewar pumped down nicely and it has been fine ever since. Thanks Elaine, you saved me a trip.
Now it is time to visit once again for some periodic service, to fix a few minor things and install some software upgrades (TCC and Ziatech). The most important task is to measure and tune the elevation and azimuth axis periodic errors. This should be done every 6 months and it is a few months overdue. Secondly, the Ziatech software will be updated to add a status word to the axis status commands and to allow the system to come up in a state with no CRT display. If these modifications work properly, the Ziatech bus traffic will be reduced significantly making Bad Reply errors even less likely than they are now (which is almost 0%). Thirdly, Frank Scinicariello will be adding circuit breakers to replace the WFCam shutter fuses.
Once again it has been a long time since my last trip. I probably should have come sooner to handle some of the maintenance items because this is going to be a busy trip. The primary purpose of the trip is to get the new 4k x 4k CCD installed on the WFCam. The goal will be to get the CCD installed, working, focused and get at least a preliminary instrument model installed. In addition, the WFCam shutter requires some maintenance as does the mirror cover. We would also like to run some tests using some new timing files on the HRCam. Much of this work requires good weather which can be tough this time of year.
Well the Monsoons are finally over and now it is time to finish up the testing and integration of the front side illuminated 4kx4k chip. Since the last Engineering visit Elaine has continued to have problems keeping a good vacuum in the dewar. She performed a leak test and found it to be air tight so we are assuming that it is contaminated. The dewar was delivered to Mike Lesser the week prior to the engineering visit for cleaning and repair of the temperature sensing Diode. Bruce will pick up the dewar on his way to the mountain.
The goals for the trip are to develop the instrument models for the WFCam, verify that the dewar can hold a good vacuum, implement and test dual serial CCD readout and create a new WFCam pointing model. In addition, spare CCD controller boards have been ordered from Leach and hopefully the new analog board will resolve the star trailing on the HRCam. Finally, if the star trail problem is resolved, the HRCam adaptive system will be tested and tuned.
Although the monsoons were over last month we got hit by the remnants of two hurricanes and the engineering trip only saw a few hours on the sky. Elaine did an excellent job of continuing the instrument block creation while Frank and Bruce worked remotely to attempt to get both amplifiers up and running. Elaine was successful and Frank and Bruce were not. The dewar has been sent back down to the Steward CCD lab for temperature tuning and electrical testing. Mike and Dave will test the CCD and verify that the wiring is intact and connected properly
The goals for the trip are to verify the operating temperature of the dewar and get the dual mode (left+right) readout working. We also want to complete the instrument model and updated the pointing model. Finally, the Elevation axis servo is due to be tuned and the instrument PC software needs to be updated to improve functionality with the software under development by Don. Bruce will also talk to Mike Lesser about helping us to debug the HRCam dewar.
This is a repair trip to fix the WFCam shutter and look for a vacuum leak in the WFCam dewar. The WFCam shutter appears to have a crinkled web so removal of the dewar and disassembly of the shutter will be required. The HRCam dewar will also be removed and sent down to Mike Lesser's lab for testing with the hope that we can find what we believe to be a wiring problem.
This is a repair trip to fix the WFCam rotator and test out the repaired HRCam CCD dewar. The WFCam rotator keeps generating an over speed sometimes at startup and then if you are successful it getting it to start up it fails at a specific rotation angle. The HRCam dewar is back from Mike Lessers lab after the discovery of a large number of cold solder joints.
This is shaping up to be a fun trip! The original purpose of the trip was to test out the replacement CCD in the HRCam, work on a problem with the Ziatech software which caused slewing halts and find out why we could not find objects in the southeast. These issues are now secondary to the primary problem which occurred 10 days prior to the trip. It appears that there has been a major power supply failure NEMA 1. Initial indicates are that the power supply for the Ziatech servo controller has failed. This is a major problem because Ziatech is no longer in business. It will therefore be necessary to identify and hopefully repair the problem.
In spite of this major problem it should be possible to perform initial testing of the replacement CCD by taking dome flats. I can also make the software modifications to the Ziatech Master.exe software but it is unlikely I will be able to test the software. Finding objects in the southeast sky needs a working telescope and without a miracle this is unlikely to happen.
We finally got the Ziatech computer up and running. This was a much longer and more difficult process than had been anticipated. The problem turned out to be multifaceted. Apparently the power supply failure either caused some additional immediate failures and/or resulted in weakened components which failed shortly afterwords during the replacement of the power supply and follow on testing. We ended up sending all of the boards and the chassis to GDCA in California. GDCA took over the rights for Ziatech manufacturing and service from Performance Technologies. They have all of the original Ziatech documentation and test equipment and they were able to test and repair all of the boards. There turned out to be quite a few failures but once the equipment was returned to Frank he was able to get the entire system up and running.
The repair process took much longer than we would have liked, but GDCA did not take over the Ziatech product line until August and Frank did not discover them until September. They then took 8 weeks to repair the boards (we believe that they did not actually have all of the test equipment up and running until after we placed the order and shipped our equipment). Although we were not impressed with the speed of their service we are grateful for their work. From the multitude of failures it is obvious that we never would have succeeded in repairing the processor on our own.
Our goals for this trip are to reinstall the Ziatech and get the telescope operational. This will take some time since we want to bring the system up carefully and make sure that all servo axes are functioning properly. Once the servo system is up and running we will need to fully test the telescope operation including cameras, filter changers, shutters etc. All of this equipment has been sitting unused for 8 months and there are bound to be other problems. Once the telescope is operational we need to test the rather odd problem which was the original reason for the May, 2004 service visit. There was a problem where the telescope was reluctant to point accurately at objects in the southeast. Perhaps this problem will solved by the extensive computer tune-up but that is unlikely. I believed that the problem was due to closely spaced requests for status words from the Ziatech. The problem only manifested itself during long slews when the rotator needed to move from one side of 0 to the other. I made a modification to STATWORD.CPP to add some delays after each bus access allowing other processes to get some bus access time. Finally, if we really have a lot of we should check out the HRCam on the sky and see if we have good images.
During out last visit in January we were able to get the Ziatech reinstalled and the servos running. As we were beginning to test the servo systems we ran into two problems. First we had trouble getting all axes started simultaneously. When we tried to run all three axes they would all suddenly halt. Just as we were starting to investigate this problem the rotator stopped working because its encoder was slipping on the drive disk. We wasted a day try to track down this problem and finally found the cause and suspected that the problem as the result of the very cold, wet weather. Elaine test the rotator once the weather warmed and it is once again working properly. We still suspect that it may need some maintenance to reduce the rotation friction in the encoder, but for now it appears to be working.
Our primary goal for this trip is to resolve the problem with the axes running simultaneously. Elaine's most recent tests seem to indicate that the problem may be related to the elevation axis. We plan to test the over-rate system and the shared memory related to the elevation servo controller. Assuming that we are able to resolve this problem, we will tune the elevation servo periodic error and then create a current pointing model.
Assuming that we get the servo problems resolved, Frank will work getting the HRCam CCD controller to boot. During our last visit we were unable to get it to function.
There are three primary goals for this trip. One goal is to get the HRCam functioning. In March we discovered that the HRCam fibers had been broken. We have since replaced those fibers but we are still unable to establish communications between jupiter and the HRCam CCD controller. The second goal is to determine and correct the cause of the occasional elevation axis servo halts. We think that the problem may be related to bad shared memory but we have not been able to confirm this hypothesis. The third goal is to identify and repair the bad elevation servo encoder bit that was identified in March.
During the June trip we had both success and failure with the HRCam. We were able to get the HRCam up and running and locked on an object. This was very encouraging seeing as how the system had not been used for well over one year. Unfortunately, the long period of inactivity also appeared to have taken its toll on the mechanics of the rotator. When exersizing the rototator both by hand and under manual servo control we discovered that the rotational friction would increase dramatically about 10 degrees after changing direction. This was very similar to a problem we saw on the main drive axes during development and was attibuted to the pinch roller. Bruce ordered new pinch roller bearings and they were installed by Hal Halbedel in late August. The purpose of this trip is to verify that the replacment of the bearing resolved the drive problem. If the repair was successful then Bruce and Elaine will move on to a project to quantitatively characterize the performance of the adaptive system.
The primary goal of this trip is to repair the WFCam shutter. We have had problems with the shutter since last December at which time it was shipped to Bruce for repair of a broken preload spring. He repaired the spring and replaced the web. Elaine and Hal tested the shutter before installation and it worked fine but after installation it locked up again.
At the end of May Elaine began experiencing problems when starting the Azimuth axis. During the startup procedure at the approximate position of where the axis initializes she would hear a loud metallic sound and the axis would fault with a tachometer overspeed. Bruce asked her to remove the diamond plate and azimuth cone covers and look to see if perhaps there was an obvious mechanical problem. When she watched the startup under these conditions she noticed that at the time when she heard the sound the motor capstan suddenly spun and slipped against the drive disk. Elaine measured the rotational friction in this area and determined that it was no different than anywhere else in the vicinity. This indicates a possible electronics problem, either with the initialization pulse or the encoder electronics. The goal of this visit is to resolve this problem.
When Elaine tried to wake the computer up from its Summer Monsoon nap she experienced a number of problems. She is unable to start up any of the servo axes, the TCC does not communicate to the Ziatech, the GPS or the Guide camera (all of the serial interface devices) and the GPS clock does not appear to want to synchronize with the satellites. These problems are symptomatic of a nearby lightning strike which may have damaged some of the sending/receiving elements.
In addition, Elaine had Frank repair an intermittent problem with the mirror cover controller over the summer and now that the controller has been reinstalled, none of the cover functions work.
The goal of this trip is to resolve as many of these issues as possible and send out for repair any components which were damages and cannot be repaired on site.
There were two major problems which need to be investigated. First, there are problems with the air panel. The first indication was that images from the telescope were triangular indicating that the primary mirror support system is not working correctly. In the process of investigating this problem Elaine was unable to start the telescope because of a persistent error No-Air fault.
The second problem is the guide camera is not working. The most recent images were pure noise.
Bruce also plans to meet with Buell Jannuzi, Tony Abraham and Mike Merrill to discuss the possibility of Kitt Peak taking over operation of Calypso.
There are two primary goals for this trip. First, the WFCam CCD controller cannot be initialized. It appears that there is a problem with the timing board because there is no carrier signal on the fiber optics board plugged into the Sun workstation
The second goal is to install and test the new server computer.
When Elaine attempted to bring up the telescope systems after the summer monsoons she had a few problems. First she was unable to get the axes to operated reliably. That problem did seem to resolve itself during some testing with the dome closed but then some of the problems returned. Initially there appeared to be problems primarily with the rotators but the elevation axis was also exhibiting problems. The rotator problems appeared to resolve be resolved after some exersize. Elaine then opened the telescope and sure enough, the rotator (left) worked fine but then the Azimuth axis appeared to stop running for no apparent reason. It sounds like there could be a problem with the Digital I/O card in the Ziatech. This is the same card that had a couple of channels fail last year (the ones that control the primary mirror cover). Frank has ordered a spare and it should be at the telescope when I arrive.
The overriding goal of this trip is to get the telescope up and running for Abi's observing test run. This involves getting the servo systems to work reliably, updating the pointing model, tuning up the HRCam AO system and verifying the image quality from both cameras.
During the last visit a few electronic issues were left unresolved. There was an intermittent electrical noise problem in the WFCam images, the primary mirror cover could not be controlled remotely and the LED's which show the rotator motor enable/disable status did not work properly. Frank is traveling to the telescope to resolve these problems. He may also need to perform some building maintenance to fix the cable for one of the building limit switches.
The primary purpose of this trip to to fix a problem with the WFCam shutter. Since late December after the passing of the large storm Elaine has had difficulty getting the WFCam shutter to initialize properly. Elaine and Hal have replace the web and both of the springs and repaired a bad cable without success.
If the shutter repair is successful and there is adequate time we will investigate the read noise of the WFCam.
Next week Abi will be observing with Elaine at Calypso to get an idea of how the telescope works and what it can do. Prior to his visit we want to make sure everything is functioning properly. My goal, therefore is to operate the telescope and make sure there are no serious glitches. There are a couple of known minor problems such as occassional shutter hangs. These are minor and can easily be recovered but I will look into whether I can fix the problem. Also, Frank is sending a new power cable for WFCam. I plan to install this cable and test the WFCam noise performance and the reliability of the camera initialization. If we get really ambitious and Elaine is available to help, I would like to replace the WFCam park pin.
In addition, Arlin Crotts has proposed a potential program for Calypso using a special, high speed CCD camera. The camera is a standard c-mount with a 1kx1k sensor and 8µm pixels. While I am here I would like to make a judgement where best to mount the camera.
Abi Saha sat in on an observing session with Elaine to get an idea of the capabilities of Calypso for NOAO. During the course of his evening he became quite interested in our WFCam CCD noise problem. This entry to the engineering diary chronicle his thoughts on the observing session and the CCD as relayed by Elaine Halbedel.
Arlin Crotts has proposed a lunar observing program for Calypso. This is a test run for that program. Arlin will supply the camera and filters. The camera is an Andor Luca 1024x1024 camera with 8 microns pixels. This camera will be mounted in place of the normal guide camera. Tracking computations have been provided as Python scripts from Russell Owen.
In addition to Arlin's project I also need to take a look at the HRCam dewar pumping problems and work on the WFCam noise problem by swapping out the timing board with our spare.
WFCam CCD Noise was examined taking dark frames.
Bruce is traveling to Tucson to meet with Abi Saha and the LSST group. LSST is interested in Calypso as a possible calibration telescope for the LSST. They would like to do some work on the telescope while in Tucson and then, if successful, move the telescope to Chile to the LSST site. In addition to these meetings Bruce plans to work on the WFCam noise problem. We are getting close as we have isolated the source to a combination of the Guide Camera booster power and the main axes being initialized. In addition Bruce also wants to repair the vacuum pump and add a frame counter to the WFCam shutter software.
After a bad thunderstorm in June, Elaine was unable to get the Ziatech to boot properly with a video display. Bruce was able to access the Ziatech remotely through the TCC but it was obvious that something was wrong. All three axes reported that they were not parked even though Elaine verified that they were indeed parked. Also, I was unable to open or close the primary mirror cover using the Ziatech and Elaine was also unable to open or close the cover using the pendant. These problems appeared to point to a failed ZT8961 digital interface card since this card controls all of these functions. Frank sent out a spare card which he had tested but it also did not work. In addition Dawn shipped back the removed ZT 8961 card and Frank verified that it was still functional. At this point we know there is a problem but we do not know where it is. The primary purpose of this trip is to resolve this problem.
In addition the vacuum pump is still not working. Elaine believes that she has pinpointed the error as a failed pressure gauge. If this is true, the pump is working properly but the gauge is faulty. She is supposed to have returned the gauge for inspection and repair. I hope that while I am in Tucson we will receive the repaired gauge and I will be able to verify that it is functioning properly.
There are a few minor problems which need to be addressed on this trip before we turn the telescope over to LSST.
The WFCam is exhibiting some odd effects on the two right side amplifiers. The right south amplifier has higher noise than the other amps and the right north amplifier has suddenly started to exhibit a level shift on saturated stars. Both of these problems may be related to the analog board. If the weather is not too dry I will swap the analog board(s) with our spare and see if that solves the problem.
We noticed last spring that the WFCam dewar window appears to have some spots from condensation. I would like to remove the dewar and clean the window. While the dewar is off I would also like to replace the WFCam park pin.
We need to verify the pointing model on both cameras and update if necessary.
While I am on the Mountain Chuck Claver has expressed an interest in working with me to start getting an understanding of the telescope.
My trip to Tucson this time is primarily for training of the LSST staff on the design and operation of Calypso. While I am in Tucson I plan to visit Calypso and perform a few minor maintenance tasks. The most important of which is routine maintenance of the WFCam shutter prior to the start of serious LSST observing. Elaine has noticed more shutter sticking lately, particularly in cold weather. The shutter used more than 1/2of the spring life so it is probably worth performing regular maintenance to make sure it is ready for the next 6 months of observing.
There are two items to address during this trip. The WFCam shutter fails to open or close about 2%-3% of actuations. It appears that when this happens the HP controller chip is in some indeterminate state where it will not respond to move commands but it will respond to a software reset and initialization. I want to add some diagnostics to log these errors when they occur. In addition I would like to add software to the shutter controller which will detect when this happens and notify the user so that they do not have to wait until the image is displayed to find out there was a problem.
The second item is a problem with the filter changer. There have been times over the past observing run where Elaine ran into problems getting the changer to change filters reliably. Many times she would get a shuttle jammed error and then she would move to a different filter and back in an attempt to clear the error. Sometimes this worked and sometimes it did not. I need to examine the shuttle motion to make sure the stage bearings are working properly and possibly fine tune the filter positions in the cassette.
We are trying something new this month. I plan to post the diary using the Wiki server provided by OS X Server. Please see the following link for the diary page:September 2009
The LSST guys want to mount a stand alone IR Camera on Calypso for a two day run September 9-10. In addition, the WFCam CCD controller was just returned to Bob Leach for service and will be reinstalled the week prior. Finally, this will be the first run after the summer storms. When all these things are combined, there is a large probability of something going wrong, hence the need for a service visit.
In addition to the observing run it is also time to handle a few maintenance items such as mirror washing and servo tuning.