From: Russet McMillan Subject: 3.5m Night Log 20020418 Date: Fri, 19 Apr 2002 06:18:20 -0600 (MDT) APACHE POINT OBSERVATORY 3.5m Telescope Night Log Thursday, April 18, 2002 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH ------------------------------------------------------------------- W.Zheng W.Zheng, K.Chiu GRIM --:-- --:-- P.Hall E.Ellingson DISII 00:50 05:50 INST SCHEDULED WEATH EQUIP OBS DAY NOTUSED I/RO/DN START FINISH D B D B D B USE D B -------------------------------------------------------------------- JH01/R 20:31 01:00 0 4.5 0 0 0 0 0 0 0 PU06/R 01:00 05:33 0.4 0.4 0.3 0 3.4 0 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- 1st Half Observing Specialist: J.Barentine Soupy skies prevented opening during the early part of first half. A dust event began at about 20:00 that persisted for a couple of hours, although the dust never went down enough nor did the sky clear enough for us to open. 2nd Half Observing Specialist: R.McMillan Dust dropped around midnight, and the clouds thinned somewhat after the instrument change. We opened when it began to look acceptable and obtained several hours of data on a single target, probably equivalent to one hour in better conditions. The seeing was quite bad when we focused because the telescope was warm; the fans had been off during first half because of the high dust counts. Later, as I pursued the changing focus, the focus improved to around 1.1 on the guider. At around 05:12, I noticed that the primary mirror readouts were showing large high-frequency oscillations in the transverse direction. It got noticeable worse over the course of a couple of minutes. I slewed the telescope up to higher altitude and successfully relaxed the mirror in a very short space of time, but unfortunately we didn't get the star back in quite the same place before resuming the exposure, so the exposure was lost. We've seen similar behavior from the mirror a few times recently, but usually after slews at low altitude. In this case, the telescope was only moving at tracking speed, and only at an altitude of 38 degrees. ------- FAILURE LOG ------- PROG INST FAILURE TIME S/E/G/D/O TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- PU06 D T/H 05:15 05:30 PMSS oscillations ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- 02:13 DISslit -200(480) 168 44 7.8/8.8 238 16 - 1.94 02:18 NA2gdr -5083(51916) 170 44 7.7/8.6 239 13 R 1.44 --------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 56 12 12 262 (W) 594 MstlyCldy none 17:01 55 11 16 224 (SW) 802 MstlyCldy none 18:01 52 11 15 227 (SW) 1329 MstlyCldy none 19:01 51 10 20 228 (SW) 1579 MstlyCldy none 20:01 50 7 16 218 (SW) 2893 MstlyCldy dust 21:01 50 7 17 192 (SSW) 3960 MstlyCldy dust 22:01 49 6 20 237 (WSW) 2335 MstlyCldy none 23:01 49 6 12 214 (SW) 1453 MstlyCldy none 00:01 48 6 12 211 (SSW) 1712 MstlyCldy none 01:01 47 7 13 228 (SW) 1482 ptly cldy none 02:01 46 9 14 243 (WSW) 866 ptly cldy none 03:01 45 11 14 238 (WSW) 812 ptly cldy none 04:01 43 10 12 249 (WSW) 825 mstly cldy none 05:01 42 14 8 262 (W) 919 ptly cldy none 06:01 41 16 11 271 (W) 1042 ptly cldy 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: 2.5.5