Date: Sat, 21 Dec 2002 06:36:02 -0700 (MST) From: Jack Dembicky Subject: 3.5m Night Log 20021220 Apache Point Observatory 3.5m Telescope Night Log Friday, December 20, 2002 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH ------------------------------------------------------------------- E.Turner J.Barentine SPIcam 17:12 19:15 E.Turner G.Miknaitis SPIcam 19:40 20:30 20:59 23:00 D.York Echelle --:-- --:-- INST SCHEDULED WEATH EQUIP OBS DAY NOTUSED I/RO/DN START FINISH D B D B D B USE D B -------------------------------------------------------------------- PU04/R 17:59 00:00 0 1.0 0 2.0 0 3.0 0 0 0 UC01/R 00:00 06:04 0 6.1 0 0 0 0 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- 1st Half Observing Specialist: J.Barentine First half started out promisingly, with virtually clear skies at sunset and light winds. I began with cals for the 2237 Lens program during twilight. After taking a complete set of flats, I moved to a focus field and started focus sweeps. During this time I noted that in the focus images, there was a distinct elongation to the stars roughly along the altitude direction. Checking the dataq, a large-amplitude, periodic signal was evident on all four load cell traces, with no sign of this noise on the valve current traces. Some investigation by moving the telescope up and down in altitude between limits of about 20 and 80 degrees showed that the oscillations began abruptly in the neighborhood of 50 degrees, although the threshold altitude where the oscillation began was not consistent, landing between about 45 and 50 degrees on different altitude sweeps. Above this threshold, the oscillations quickly damped out. Russet logged in from home after I alerted her to the problem. I switched over to the Shack-Hartman and brought up a star on the video monitor which showed clear, subsecond-frequency vibrations along an direction most closely identified with altitude. The amplitude of the vibrations was worse than the apparent seeing variations around 50 degrees altitude. I consulted Mark by phone who recommended a series of operations involving hauling the telescope down to the lower altitude limit and up as far as the zenith. Russet then volunteered to come in to help. While I monitored the dataq downstairs, Russet hauled the telescope manually down to the lower altitude limit and back up a couple of times. I then did test slews after this while she remained on the observing level. Repeated slews between 80 and 15 degrees altitude showed a marked decrease in the amplitude of residual oscillations after slews completed. We decided, with Mark's assent, to continue to operate with slight degredation of the images due to what remained of the oscillations on the dataq. Russet's conclusion is that PMSS tuning is at fault and retuning is called for within a week or so. I handed things over to Gajus until near 23:00 when the wind speed crested the closure limit. Clouds began to move in around midnight. 2nd Half Observing Specialist: J.Dembicky Very gusty winds for the 2nd half. The wind gusts stayed above closure levels until around 05:15 at which time the winds started to drop and the humidity started to climb. The observer gave up around 05:30 as 30 mins was not enough time to get anything useful, especially since it would probably take me 15 mins to get everything up and running and then focused. The PMSS was calm when I tied the telescope down at 10 deg. ------- FAILURE LOG ------- PROG INST FAILURE MODE TIME (SEGDFVO) TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- PU04 S T/H 19:00 21:00 Strong PMSS load cell oscillations below 50 deg altitude ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- 19:46 SPIcam -100(429) 121 69 -1.3/-1.4 198 24 r' 1.00 20:21 NA2gdr 211(61211) 189 56 -1.3/-1.6 206 27 R 1.96 21:17 SPIcam -100(405) 212 52 -3.2/-2.8 207 22 r' 1.5 22:39 NA2gdr -1266(59733)236 40 -2.7/-3.3 208 30 R 2.03 --------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 32 -12 15 207 (SSW) 87 MstlyClr none 17:01 29 -16 14 204 (SSW) 78 MstlyClr none 18:01 28 -16 16 205 (SSW) 79 Clear none 19:01 31 -13 22 218 (SW) 48 Clear none 20:01 30 -14 27 213 (SSW) 51 Clear none 21:01 27 -4 24 201 (SSW) 134 Clear none 22:01 27 -4 26 208 (SSW) 153 Clear none 23:01 27 -3 27 218 (SW) 113 Clear none 00:01 25 -3 34 241 (WSW) 190 MstlyCldy none 01:01 22 5 26 267 (W) 284 MstlyCldy none 02:01 23 4 31 253 (WSW) 253 Pt Cldy none 03:01 20 7 27 267 (W) 380 Mst. Clr none 04:01 19 8 30 289 (WNW) 573 Clear none 05:01 18 9 24 284 (WNW) 613 Clear none 06:01 16 11 14 293 (WNW) 1051 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