2003 June IOTA Log (MONNIER) -------------------------------------------------------- After a week of suffering by Rafael and company to get the delay lines working, our YSO observing run enjoyed 2 weeks of clear weather (although bad seeing) and we acquired lots of closure phase data. -------------------------------------------------------- I will start with the good news: Noticable Improvements ---------------------- a. Star acquisition -- framegrabbers rock. b. Laser light (better baffling). I had almost no problems with laser light (a little bit on one night on a really faint source). c. (Almost) no OT crashes d. Alignment LEDs good e. Roll limits moved to ~ -69deg (extended from -63 deg). VERY helpful (thanks marc). f. 'Acquire' pull-down buttons are handy on star tracker control (thanks pete)! g. I fixed bug in way sd offsets were given by fringe tracker h. Allows all kinds of scannning strategies (plus/ minus slopes on ramps) --changed defaults to avoid 'double-packet' problem. Also, the iota*.ofs file contains the piezo offset positions for each scan so one can eliminate data when the fringe is too near the scan edge. Currently piezo 1 scans 50 microns OPD in 'plus' direction and piezo2 scans 50 microns in the 'minus' direction' i. FIXED the problem with the bad timing patterns. DAQ would sometime not load proper timing pattern. I added some timing controls (wait statements) and it seems ok now. j. Short delay glitch fixed last fall by Pete (proper interpolation of vel position) k. Mechanical spots for retros for aligning fiber good! l. Way to see pupil is great -- I like the 50/50 beamsplitters m. Fixed fringe tracker 'bug' so that it doesn't send offsets to piezo if no fringes are found. However, it still does send small offsets to DL line which can cause some problems if you keep the Fringe Tracker 'Locked' while there are no fringes [i.e., still turn this off]. --------------------------------------------------------- And now the bad news... Remaining Problems ------------------ 0. We need to automate yaw adjustment. 1. Tel focus: must change focus when going between N/S delayed.. see accompanying memo on some current good positions. 2. Would be nice if the PICNIC detector was continuously read out. As it is, we have to throw out the first 10 or so scans because the chip gets flooded and it takes time for the resets to take effect -- or maybe each reset should be longer? 3. For Delay paddle - nice to add a paddle which will keep the DL1-DL2 fringe. That is, one that will increment SD1/SD2 the same amount. 4. Color table problems on left of 2-headed iota monitor. VERY annoying. requires logging in and out for no good reason. Can we get either a better video card or learn how to set up the config settings? 5. OT: Why do the Bright Star Catalog entries always get entered with a number in front of the name?? Also, I can't figure out how to use the online catalogs. 6. Would be nice if there was a way to stop taking fringes after starting a set. 7. Vignetting still a problem -- especially for weak sources when every photon counts. Suggestions: a) redo star tracker mirror mounts to be xy, not 0,120,240 degree mounts. b) put picomotors on these c) set up a pupil imaging system like on the old system d) can we do this when we upgrade to the new CCD? 8. Very rarely the short delay line will have a fault for no apparent reason: (happened once to me, 3x for Rafael). Reseting SD fixes it, but.. ?? No idea why. 9. In Delay Search, the 'step' should not be sign dependent, but rather automatically go between the two bounds -- no? 10. The fringe tracking finder "Delay Search" on the OT seems to have gotten worse. Often the background process does not pick up that there are actual fringes there. One can see on the screen they are indeed found, but the the Delay Search program is not stopped. Maybe there is a small synchronization problem -- It does seem like the background search program is moving along faster than before (maybe too fast). 11. "Delay Search" should be able to do both DL1 and DL2 at the same time... 12. Catalog -- we really need a writer for this so that we can stop entering all these coordinate by hand intot he OT for each run 13. Baseline / Pointing model fits.. Still very awkward. Hurts efficiency a lot. Evidence: apparently I am the only one that ever does these! 14. Bad Tel foci limits sensitivity by probably (at least) 1 magnitude. 15. Shutter C occasionally sticks open. By the way, I think we can all agree these shutters suck. We probably should be imagining replacing them since I can't believe they will last long. 16. PM search on star tracker should be an outgoing spiral, not a grid search starting from the point from the star! (No big deal for bright stars, but causes big waits for faint stars with small steps.) 17. Why is the FIX(A) Telescope lower than others by 50% in visible? We should figure out if it's a mirror/window or what... We looked at the pupils and its not vignetting in any obvious way -- (although the pupil for A/fix seems like the edges are not fully illuminated...) When I switched to B Fix, the weak telescope seemed to flip also, indicating some mirror/window in the North Telescope train, not the Fix delay train. 18. The laser hut needs to be better ventilated. The laser alignment seems to go out a lot on the LDs and this probably is because the room gets quite hot. The little teensy fan in there already was a good try, but is very weak. [Evidence: I started the night and the LD1 laser was around 0 V. I opened the hut door and the voltage is slowly rising up to its normal level as the room cools down. After about 15 minutes, the alignment was recovered.] 19. Alternatively, we should redo the mounting of the optical table in the laser hut to be less temperature dependent. I had to readjust the long delay lasers about every other night, which is PRETTY annoying. 20. We should not make it required to tell Star tracker which telescope is delayed. 21. Color table problems. Way for IDL and startracker to share color table, etc. Given the cheapness of video memory, I find this particular annoyance avoidable. 22. Why is there so little throughput for the 'narrow' band filters? Image quality? 23. SDelay should be able to be 'homed' even in the 'Command' position is out of range.. no? 24. Sdelay should check not to hit each other. I do it fairly often. 25. OT complains WAY too often about short delay position -- why? Why must we put it in fixed mode when we want to do stuff w/o interruption? Just because the star track position is out of SD range doesn't seem to have anything to do with telescope functions, long delay, etc. 26. When using 'acquire star' on star tracker too, the computer should first look to see if it's there before running off and doing a PM piezo search. 27. I couldn't find the CD ROM burners. We should have some way to burn these easily for our data backups.