Date: Sun, 24 Nov 2002 05:18:23 -0700 (MST) From: John Barentine Subject: 3.5m Night Log 20021123 Apache Point Observatory 3.5m Telescope Night Log Saturday, November 23, 2002 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH ------------------------------------------------------------------- G.Wallerstein V.Woolf Echelle 17:55 01:25 INST SCHEDULED WEATH EQUIP OBS DAY NOTUSED I/RO/DN START FINISH D B D B D B USE D B -------------------------------------------------------------------- UW03/O 17:55 05:45 0 0 0 4.3 2.1 5.4 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- 1st Half Observing Specialist: B.Ketzeback The first half went well even though we were shooting through some clouds. The seeing was moderate. There really was no evidence of the tracking problems that were seen the second halfs the past few nights. The PMSS remained quiet and there were no large tracking jumps or elongations with the echelle slitviewer. 2nd Half Observing Specialist: J.Barentine Second half began unremarkably and even looked promising as the sky began to slowly clear from the west. Then everything fell apart. Just before 01:25, after his exposure had finished, Vincent noticed that his program star had vanished from the guider in the interval between the last time he looked at the guider window and when the Echelle exposure finished. I tried a couple of tests to determine first whether it was a pointing issue, but the trails on the NA1 guider (image /export/images/na1_trails.fit) suggested an outright tracking failure. I hailed Russet on the telephone for additional ideas. First she suggested checking the enclosure controller, which I did, though that inspection revealed an apparently clean bill of health. Running a TCC session from home, she was unable to communicate with the azimuth controller, but from the logs she found erratic tracking behavior and increasingly large NA1 guider offsets beginning at 01:14. Checking the cache of recent guider images, I found one taken evidently at the moment tracking failed (/export/images/na1_azstop.fit). It shows the star making a quick exit along the azimuth direction, according to the focal plane diagram in the TUI. The successive two guider images show the star neatly tracking away from the slit. The next suggestion was to reset the azimuth controller box. Going upstairs and finding no convenient external method of doing this, I opened the front panel and power cycled the two power strips as well as the bus controller card. Still so sign of communication between the TCC and the az controller. Russet suggested calling Mark for information on how to gracefully reset the controller as well as his input on whether we should declare the night a wash and close. Mark responded that power cycling the controller was definitely an ungraceful way to reset things, but told me that everything appearing to have come up successfully, resetting the bus card once more might clear things. I did that but it didn't resolve the problem. Russet suggested resetting the enclosure controller whether the lights looked wrong or not, which I did. After that the TCC was reporting stop buttons in which weren't, though resetting some TCC things evidently fixed the problem. Russet tried some short azimuth moves which resulted in the enclosure moving, yet the LVDT trace went way up during the moves, suggesting that the azimuth motors were actually not moving and the enclosure was dragging the telescope along. At this point, with the LVDT results and odd noises on the intercom, I hit a stop button and Russet suggested we call Craig. Just before doing so, I told Vincent that it was unlikely we were going to get anything useful out of the remainder of the night, so I was pre-emptively declaring science suspended until further notice. Craig gave the problem some thought. Russet knew that even if we did get the azimuth motor working properly, the scope would be severely lost in azimuth, requiring a drive remap before we could recommence with any science. When she tried initializing a remap, the scope failed to slew with an evident motor overcurrent, as the velocity of the initial slew in a remap is well above the recently-instated lower velocity limit. Giving it the old college try, Craig sent me up to the intermediate level with my laptop to try to command moves from there and listen to whether the odd noises were coming from the motor box on the azimuth drive (a fatal event) or the enclosure (a little more benign). But while looking over data from the az motor controller, he decided that things looked worrisome enough to not attempt to continue tonight. I closed the enclosure at 04:00. See Russet's PR (ID 2002232) for another description of events with additional technical information. ------- FAILURE LOG ------- PROG INST FAILURE MODE TIME (SEGDFVO) TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- UW03 E T/H 01:20 --:-- Azimuth tracking failure ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- 18:51 Echelle -78(-217) 174 57 7.2/7.8 250 19 clear 1.1 --------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 47 9 11 205 (SSW) 144 Mstly Cldy None 17:01 44 8 10 214 (SW) 157 Mstly Cldy None 18:01 45 5 14 226 (SW) 107 Mstly Cldy None 19:01 46 3 18 239 (WSW) 240 Mstly Cldy None 20:01 45 4 15 239 (WSW) 354 Mstly Cldy None 21:01 44 5 12 258 (WSW) 382 Mstly Cldy None 22:01 43 5 14 245 (WSW) 421 Mstly Cldy None 23:01 42 6 12 243 (WSW) 516 Mstly Cldy None 00:01 41 7 18 263 (W) 657 Mstly Cldy None 01:01 41 6 20 265 (W) 500 PtlyCldy None 02:01 39 5 19 267 (W) 502 MstlyClear None 03:01 39 4 14 292 (WNW) 450 Clear None 04:01 39 2 19 267 (W) 313 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 Primary, secondary, and tertiary mirrors in place and collimated. Primary support system operational. Mirror ventilation system in place. Telescope drives operational. Current Remark version: 2.82 Current guide software version: GIm Ctrlv4.1b2 Current TCC version: 2.6.8