From: "Camron Hastings" Subject: 3.5-meter Night Log 980623 Date: Wed, 24 Jun 1998 05:26:21 -0600 Tuesday, June 23rd, 1998 APACHE POINT OBSERVATORY 3.5-Meter Observing Log ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT DATE START FINISH ---------------------------------------------------------------------- Tremaine T/H/G* SPIcam 6/23-24 21:57 01:10 Margon Margon/Deutsch SPIcam 6/24 01:10 03:34 Turner C. Hastings SPIcam 6/24 03:34 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 3.2 - 0 - 0.0 - 0 0 - UW11/R 01:10 03:34 1.8 - 0 - 0.6 - 0 0 - PU01/S 03:34 04:14 0.7 - 0 - 0.0 - 0 0 - ACTIVITY LOG Enclosure was opened at 20:15 with clear skies, dust count low, and the winds were calm. All systems operating nominally. We did have a mirror support system alarm due to the positive pressure hovering near the lower limit. This was rectified, with the help of Chris Stubbs and Yorke Brown, by adjusting the positive pressure to a new value of 39lbs per sq inch. This was up form the 36-37 previously noted. The TNO team started on time with no equipment problems. It is good to note that they identified 2 of the 3 TNO objects they had hoped to see last night. They were plagued with focus drift through the early and middle sections of their run. It seems the temp differential (1-2dg) between the ambient and truss is too much for the secondary to handle, and is quite an issue for the 450 second exposures being done. Multiple focus attempts were needing, including refocusing of the guider each time, which absorbed a good percentage of time. I recommend cooling the structure as SOON as possible to bring truss/ambient in line. Second, their image quality was reduced by 0.2"-0.5" possibly by tracking issues, depending on the place in the sky. Some looks like guider correction, some looks like tracking problems, and some just high airmass. In the future we will do a pointing/tracking correction with each slew to help eliminate any pointing errors that may introduce degradation. This was tried during the next run, and there was noticeable improvement. The UW run started nearly on time after a filter wheel switch. The first attempt at focus was hampered by very poor tracking. This was counteracted by stopping the motors, re-initializing, slewing back to the field, and then doing a pointing correction. After that we obtained 0.88" seeing, and guided exposures of 100s yielded 0.99" images. OBSERVER'S COMMENTS ---------------------------------------------------------------------- Last night (22-23 June) went smoothly. particularly since we had not used this telescope or instrument before. The data were good enough that we were able to recover two of three Kuiper belt objects that move fast enough to be detected in a single night. These were 1995 JQ1 and 1995 KV1. This is especially encouraging since the conditions were below average. The pointing "problems" that we thought we had experienced were due to our having finder charts for positions of the objects on different nights and to not precessing the positions of the standard fields from 1950 to 2000. This will not be a problem tonight. (OBS NOTE: We slewed to 2 fields that were unidentifiable, then gave up and slewed to the next object. I suspected this was the issue and did not mention it in the previous night log) Minor glitches and comments: 1.'eveflat' did not function correctly. 2.Being able to do dome flats might make having a "drop in" KBO recovery program easier since a different instrument might be used on the night of the observations and thus sky flats would not be available. The dome flats that we tried were terrible. 3. For on site astrometry having the STSDAS and FINDER IRAF packages are necessary. Warren has his own software, but these packages would be easier for the APO astronomers to use. 4. We saw apparent guiding problems on several of our 8 minute exposures. This manifest itself as elongated images. However, the guiding overhead was acceptable. ---------------------------------------------------------------------- After a rocky start, we ended having a short but very productive run. Skies were photometric with good seeing. When we got the telescope, we tried focussing first off after slewing to our target field, but couldn't get a consistent focus value. After starting guiding while trying to understand the puzzling focus results, we saw that the telescope was drifting 0.6 arcsec every 10 seconds (the guider was valiantly trying to correct for this). At this point Camron reinited some things and did some pointing corrections (40 mins spent in all figuring this out and fixing). When this was completed, pointing and tracking were very good and a new focus frame gave very good results (0.8 arcsec). It may be a good idea to do a pointing correction every time when starting a run to make sure tracking and pointing are good. For the remainder of our 1.7 hr we took many 100 sec exposures reading out only the bottom half of the SPIcam CCD for lower overhead; the instrument behaved very well. There was one focus drift where the focus got progressively worse over 4 min. Nudging the focus higher by 50 units improved the focus considerably, yielding 0.8 arcsec images in 100 sec, although the PSF shape was clearly still not optimal. There was no time left to try a focus to see how good seeing really was. The guider seemed to be getting 0.7 arcseconds, but is undersampled at this FWHM. No problems at all with the guider tonight; the curious striping even seemed to go away after a while (striping was bad at the start, but completely gone by the end). I set up the Guider Monitor program to display on tycho as a test, and that worked very well; this could probably be done on a more regular basis, but we'll need to test a bit more. ---------------------------------------------------------------------- FOCUS LOG June 23rd, 1998 Best Telescope Temp Wind Seeing Time Instrmt Focus Az El Air/Truss Dir MPH filter FWHM" ---------------------------------------------------------------------- 21:25 SPIcam -120/6841 223 48 19.1/20.4 266 11 r' 0.83" 22:35 SPIcam -230/6732 210 40 19.3/19.6 221 19 r' 1.20" 22:15 SPIcam -260/6744 234 31 18.9/19.4 215 11 r' 1.16" 02:05 SPIcam -350/6395 166 81 17.8/18.0 322 8 V 0.88" 04:05 SPIcam -300/6484 151 77 17.2/17.5 270 8 r' 0.88" WEATHER LOG June 23rd, 1998 Wind Time Temp-F Dewp-F MPH Direction Dust Sky Precip ------------------------------------------------------------------ 16:01 71 21 12 264 (W) 650 clear none 17:01 78 26 13 262 (W) 699 clear none 18:01 75 26 15 260 (W) 632 clear none 19:01 71 23 17 267 (W) 674 clear none 20:01 68 22 11 225 (SW) 672 clear none 21:01 65 22 13 212 (SSW) 767 clear none 22:01 66 22 12 203 (SSW) 815 clear none 23:01 67 22 14 217 (SW) 820 clear none 00:01 66 21 7 260 (W) 837 clear none 01:01 65 19 5 299 (WNW) 966 clear none 02:01 64 20 8 308 (NW) 832 clear none 03:01 64 20 10 323 (NW) 775 clear none 04:01 63 20 8 310 (NW) 754 clear none 05:01 63 21 7 268 (W) 757 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