Date: Sat, 5 Sep 1998 06:25:44 -0600 From: tia@tycho.apo.nmsu.edu (Tia Hoyes) Subject: 3.5m obslog 980904 FRIDAY SEPTEMBER 4, 1998 APACHE POINT OBSERVATORY OBSERVING LOG ACTUAL ASTRONOMER OBSERVER INSTRUMENT DATE START FINISH Bohm Crespo GRIM2 9/04 19:30 00:35 Turner Hoyes DIS 9/04 ----- ----- Bohm Crespo GRIM2 9/04 ----- ----- INST SCHEDULED OBS WEATH EQUIP DAY NOTUSED I/RS/DN START FINISH D B D B D B USE D B UW08/R 20:49 00:20 0 3.5 0 0 0 0 0 0 0 PU01/S 00:20 01:10 0 0 0 0 0 0.8 0 0 0 UW08/R 01:10 05:16 0 0 0 0 0 4.1 0 0 0 (note: times listed include instrument change time) ACTIVITY LOG The telescope was opened at 20:50. Alberto Noriega-Crespo was observing for the evening with the exception of Lens Monitoring. The observing seemed to be going well, until I did the instrument change for the Lens Monitoring run. At this time, the rotator began having serious runaway problems. I would initialize the axis, and the rotator would immediately spin with much force to the right. I tried to stop the motors and reinitialize and send the rotator to zero, but this world not work. I was up on the observing level watching this happen: *turned the motors off *moved rotator back to zero by hand *turned the motors back on *rotator would spin to the right out of control at very high speeds *motors off again *reset rotator by hand *motors on *this time I got to axis init, and the rotator sped out of control again After trying a host session and a remap, both of which caused the rotator to spiral out of control, I proceeded to look at the cabling coming from the rotator. It looked like it had been yanked but the force of the runaways. I discussed the problem with Alberto, and by this time it was close to 3AM. We could not observe due to the fact I could not initialize the axis without the rotator running away at a high velocity. Therefore, we stopped for the night. Lens Monitoring was not done due to rotator problems. COMMENTS: This note is to report the problems that Tia Hoyes and I encountered with the Rotator on the night of Sep 4, 1998 UT. The telescope was apparently behaving well until the moment that it was necessary to take off GRIM from the telescope to be replaced by DIS, at approximately 12:35am. However, looking at my last 3 images, it is clear that my object was not aligned anymore with the N-E orientation. Indeed my last image is off by some 80-90 degrees. At approximately 1:20am, Tia sent me a message to tell me that the rotator was hung, and that she will try to fix it. It was time in any case to put back GRIM to continue with my observations. We never recovered from this. Despite Tia's best effort, the rotator was spinning off very fast and it couldn't be set or rest properly. Because of this, and concerned that we have a major problem, at about 2:15am we decided to close the dome and to stop my observations. I want to thank Tia or her help. As I said right before the change of instruments I was having a good observing night. Regards, Alberto Noriega-Crespo Forecast:(4:30am) .TODAY...FAIR THIS MORNING AND PARTLY CLOUDY IN THE AFTERNOON. .TONIGHT...FAIR SKIES. .SUNDAY...FAIR DURING THE MORNING. PARTLY CLOUDY IN THE AFTERNOON WITH ISOLATED THUNDERSTORMS. .OUTLOOK FOR LABOR DAY...PARTLY CLOUDY WITH A FEW AFTERNOON THUNDERSTORMS. (* means a trouble report has been issued or appended to) FOCUS LOG SEPTEMBER 4, 1998 Best Telescope Wind Seeing Time Inst Focus Az El Temp# Dir MPH filter FWHM " 21:00 GRIM2 +200(7034) 194.2 32.5 ?/16.71 98.6 11.5 2.122 1.24 22:30 GRIM2 -50(6781) 14.2 54.5 ?/14.27 109.3 23.8 2.122 1.14 # The first temp is air, the second is truss, both in degrees C. WEATHER SEPTEMBER 4, 1998 Wind Time Temp F Dewp. MPH. Dir. DUST Sky Precip. 16:01 32 32 6 120 (ESE) 616 overcast none 17:01 32 32 12 109 (ESE) 645 overcast none 18:01 32 32 14 109 (ESE) 653 mostly cloudy none 19:01 32 32 11 104 (ESE) 764 clearing none 20:01 32 32 12 78 (ENE) 785 clearing none 21:01 32 32 15 85 (E) 845 mostly clear none 22:01 32 32 22 108 (ESE) 970 clear none 23:01 32 32 22 105 (ESE) 1031 clear none 00:01 32 32 12 107 (ESE) 1036 clear none 01:01 32 32 15 112 (ESE) 1220 clear none 02:01 32 32 20 124 (SE) 1056 clear none 03:01 32 32 13 124 (SE) 1058 clear none 04:01 32 32 16 129 (SE) 1150 clear none 05:01 32 32 16 124 (SE) 1041 clear none 06:01 32 32 11 97 (E) 1065 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 >1 micron per 0.1 cu. ft. 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: 2.42a Current guide software version:GIm Ctrl v3.0b 15.out -Tia