From: "Camron Hastings" Subject: 3.5-meter Night Log 980624 Date: Thu, 25 Jun 1998 06:27:00 -0600 Wednesday, June 24th, 1998 APACHE POINT OBSERVATORY 3.5-Meter Observing Log ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT DATE START FINISH ---------------------------------------------------------------------- Tremaine T/H/G* SPIcam 6/24-25 21:57 00:55 Kron B.Holden DIS 6/25 01:25 04:14 *Tremaine/Holman/Gladman INST SCHEDULED OBS WEATH EQUIP DAY NOTUSED I/RS/DN START FINISH D B D B D B USE D B ---------------------------------------------------------------------- PU03/S 21:57 01:10 3.0 - 0.0 - 0.0 - 0 0 - OC05/R 01:25 04:14 2.4 - 0.2 - 0.2 - 0 0 - ACTIVITY LOG Enclosure was opened at 19:30 this evening. We tried the early opening to help equalize the truss with the ambient temp to avoid the focus drift. It seems to have helped somewhat with the secondary "popping" because we started at a much more reasonable value for the focus this evening. The seeing was degraded by the long exposures, but at times it seems to have exceeding what was reasonable for exposures of such duration. We tried multiple ways to counteract this, but at times lost as much as 0.4"-0.5" do to tracking type problems. The guider definitely helps when there is a star of sufficient mag to allow the guider to offset at intervals of about 10 seconds. All in all, I feel the TNO group had a successful run, though it would have been greatly improved with more consistent tracking/guiding. It should be mentioned that we tried to re-install the previous pointing model to see if that might help correct the tracking issues. It seemed worse on the first frame tried, so we returned to the most recent version. The second run started with DIS, and all was prepared and planned much better than the previous. I felt that every task went smoothly and each step carried out efficiently. There was one glitch to mention. At around 02:55 the focus made a jump. I wonder if this was one of the secondary tension release effects discussed earlier. The focus jumped from -280 to about -50 in the span of about 5-10mins. This was first noticed by the use of Eric Deutsch's guider IDL display now in use. The FWHM of the guide star went from .78" at best to 6.2" very suddenly. As we were in the middle of an exposure, I assumed this was a secondary related focus shift, confirmed by the slit camera, and I just started cranking the focus up. At around -50 we attained a value that allowed reasonable guider FWHM. After that exposure we checked focus roughly and found that value of -50 to be correct. This item should be looked into during the shutdown if not already scheduled. OBSERVER'S COMMENTS ---------------------------------------------------------------------- Somewhat successful observing run. One glitch cost us some time and slight weather problems. No instrument problems, got most of the data we wanted. cheers brad ---------------------------------------------------------------------- FOCUS LOG June 24th, 1998 Best Telescope Temp Wind Seeing Time Instrmt Focus Az El Air/Truss Dir MPH filter FWHM" ---------------------------------------------------------------------- 21:25 SPIcam -310/6669 -136 48 20.1/21.0 266 11 r' 0.78" 01:30 DIS -280/6815 74 33 18.6/18.8 299 14 gunn r 1.15" 01:40 Guider 55519 74 33 18.6/18.7 299 14 r 0.79" WEATHER LOG June 24th, 1998 Wind Time Temp-F Dewp-F MPH Direction Dust Sky Precip ------------------------------------------------------------------ 16:01 76 30 22 262 (W) 542 prtly cldy none 17:01 72 25 15 255 (WSW) 520 prtly cldy none 18:01 74 28 14 238 (WSW) 625 prtly cldy none 19:01 71 28 15 269 (W) 733 prtly cldy none 20:01 69 28 11 232 (SW) 724 clear none 21:01 67 27 14 248 (WSW) 824 prtly cldy none 22:01 69 27 13 261 (W) 721 clear none 23:01 67 30 13 274 (W) 920 clear none 00:01 66 30 14 294 (WNW) 733 mstly clear none 01:01 65 30 7 294 (WNW) 651 clear none 02:01 65 30 14 300 (WNW) 968 clear none 03:01 64 31 13 308 (NW) 1047 mstly clear none 04:01 63 31 11 313 (NW) 981 clear none 05:01 64 30 6 309 (NW) 721 mstly clear none 06:01 63 31 13 329 (NNW) 679 mstly 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 for the 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: 2.41a Current guide software version: GIm Ctrl v3.0b 15.out - Camron Hastings