From: Russet McMillan Subject: 3.5m Night Log 20060413 Date: Fri, 14 Apr 2006 06:13:48 -0600 (MDT) Apache Point Observatory 3.5m Telescope Night Log Thursday, April 13, 2006 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH -------------------------------------------------------------------- M.Klaene R.McMillan,C.Loomis, DISslit,NA2gdr, 20:45 05:40 W.West Echslit,NIC-FPS, SPIcam,SH, APOLLO-STV INST SCHED(TWILIGHT) WEATH EQUIP OBS DAY NOT USED I/ROW/DN START FINISH D B D B D B USE D B ---------------------------------------------------------------------- EN01/W 20:27 05:40 0 0.3 0 0 0 9.0 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: R.McMillan This was a very hectic and challenging night with many problems -- most resolved, but some still poorly understood. We made lots of progress in the area of software. The night started out with heavy clouds and nearby precipitation on radar, so I knew we wouldn't be opening at sunset. I got the telescope tracking with the dome closed, and Craig Loomis and I played around a little with some of the new guider software while discussing some of the recent mysterious troubles with pointing and image elongation. I also did some tests of SPIcam operations with the new ICC. After 20:30 the radar cleared and the clouds thinned, so I opened up. We had some trouble slewing with new slew parameters, which frequently caused moves to abort because the axes were too slow to respond. After trying several variations and encountering the same problem several times, Craig called Russell Owen and they worked out a solution. Meanwhile, whenever we did complete a slew, I was disturbed to see that pointing with DIS was off by several arcminutes. Together, Craig and I tested some new improvements to guiding software and found only very minor quibbles. At the end of this testing, Craig discovered more serious problems with some less-likely but not impossible command combinations, and resolved that he would have to work on that later. I tested the pointing further and learned that fixing it with the tertiary would require a tilt change of 800 arcseconds, which I was reluctant to do. I knew that some minor work had been done on the tertiary mirror during the day, with several things being checked out but nothing replaced. I didn't think that could account for the pointing trouble (especially since there have been intermittent pointing irregularities at various ports for several weeks), but I wasn't certain. Finally I decided to home the tertiary mirror, a two-person job that was accomplished with the assistance of a visitor. Unfortunately, this still didn't improve the pointing. Objects were coming up at the very edge of the DIS slitviewer or NA2 guider fields, and completely off the echelle slitviewer field of view. Since I didn't think the tertiary was the cause of the pointing problem, I didn't want to fix it by tilting the tertiary. So after figuring out some offsets that would get a star onto the guider field of view, I tried to do a pointing model -- only to find that the pointing model software was broken by the recent changes to guiding. With the pointing borderline unusable and a proper pointing model impossible, I had to make the fix by changing tertiary tilts. I did this at NA2, then made some pointing checks around the sky. Before switching to other ports, I meant to test dither scripts with NIC-FPS to get a feel for whether the new, faster computed offsets could be used in place of uncomputed offsets. Unfortunately, I found the dither script software was also broken, so I gave up on that pretty quickly. Offsets ARE much quicker now, we know that; I estimate that there would be little time lost and much trouble saved by using computed offsets in NIC dither scripts, but I don't have a quantitative value for the (small, I think) time loss. I switched to the Shack-Hartmann, adjusted tertiary tilts to fix pointing at that port, did a quick check of collimation (fine -- it clearly isn't the secondary or primary that caused the pointing problems), and moved on to adjust tertiary tilts for the echelle. Then I did the same for APOLLO. I didn't do Fastcam (Sorry, Bill). I returned to the echelle and then back to NA2 to re-check pointing, and found that it was consistent at least on few-hour timescales. I finished up with a few more SPIcam tests, including the morning flat script. Since we don't know the original cause of the recent pointing problems (nor why they were intermittent and irregular before tonight), we don't know when or if they might recur. A sudden, large change like this is not the usual pattern for this telescope and is disturbing as well as puzzling. It would be desirable to get a new pointing model so that we can get a better idea of what has changed, but it may not be worth pre-empting scheduled science so long as pointing remains consistent. ------- FAILURE LOG ------- PROG INST FAILURE MODE TIME (SEDFNVOG) TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- 03:21 NICFPS 150(1563) 92 66 12.6/12.2 278 11 J 0.76 03:41 S-H -90(1631) 6 62 12.6/12.2 284 11 - v.good ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 65 33 13 180 (S) 1296 cloudy none 17:01 61 33 2 165 (SSE) 1254 cloudy none 18:01 60 32 14 183 (S) 1274 cloudy none 19:01 58 32 14 182 (S) 1478 mstly cldy none 20:01 57 32 11 178 (S) 1613 mstly cldy none 21:01 58 30 13 185 (S) 1528 mstly cldy none 22:01 58 31 15 203 (SSW) 1481 ptly cldy none 23:01 57 30 15 207 (SSW) 1551 ptly cldy none 00:01 57 29 10 191 (S) 1426 ptly cldy none 01:01 56 30 12 201 (SSW) 1495 ptly cldy none 02:01 55 30 9 225 (SW) 1388 mstly clr none 03:01 55 19 8 269 (W) 981 mstly clr none 04:01 55 16 13 291 (WNW) 964 clear none 05:01 55 13 14 282 (WNW) 970 clear none 06:01 54 12 15 295 (WNW) 935 clear none Note: the wind was coming from the azimuth listed. The convention used is north=0 degrees, east=90 degrees. The dust count is particles > 1u per 0.1 cubic feet. TELESCOPE STATUS Telescope drives operational. Current TCC version: 2.8.2 Current TUI version: TUI 1.1