From: Russet McMillan Subject: 3.5m Night Log 20051014 Date: Sat, 15 Oct 2005 06:04:15 -0600 (MDT) Apache Point Observatory 3.5m Telescope Night Log Friday, October 14, 2005 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH -------------------------------------------------------------------- D.York G.Stringfellow DIS 19:20 22:10 J.Wilson J.Wilson,M.Nelson CorMASS 03:05 03:40 INST SCHED(TWILIGHT) WEATH EQUIP OBS DAY NOT USED I/ROW/DN START FINISH D B D B D B USE D B ---------------------------------------------------------------------- UC04/R 19:26 00:50 0 2.7 0 0 0 2.7 0 0 0 DD02/O 00:50 06:13 1.2 3.6 0 0 0 0.6 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: R.McMillan A very difficult weather night. The forecast was somewhat dire, calling for a low-pressure system to bring in storms from Mexico (the same system that was supposed to have moved in 36 hours earlier). There were low-altitude clouds lurking about before sunset, and humidity was unpromising. But conditions right at sunset were not so bad, so I elected to open. We struggled to observe through a variety of rapidly-changing clouds until it reached the point where a 3rd magnitude standard was no longer visible; then I closed. A few sucker holes provided temptation, but I resisted when the humidity popped up to over 90%. After careful inspection of the conditions outside, I decided I didn't believe the humidity was really that high, but by then the clouds had closed in again. I put some effort into determining a real value for the humidity, with little luck. My own estimate based on condensation on railings, cloudcam, cars, and catwalk surfaces was about 70-75%; our dewpoint sensor said 90%; the Sloan dewpoint sensor said 55%; the press fan hygrometer said 98%; and I couldn't find the sling psychrometer. The point was moot so long as clouds lingered, but it was still very frustrating. We also had a number of equipment problems, although technically they didn't cost any observing time. The first was a problem with the echelle, which could not read images -- a data cable was unhappy after tests on the new ICC. This problem was not fixed until after 20:00, so the echelle (the first requested instrument) was not available at the start of observing, and the observer had to go with a backup instrument. The echelle slitviewer also needed to be kicked several times before it was ready to work. The DIS blue camera had a temperature excursion of unknown cause in the late afternoon, warming 30 degrees in an hour and then cooling again as rapidly, without noticeable effect on bias level. The rotator overcurrented at 22:51 MDT (DIS, rotation -131, tracking quietly) shortly before I closed in the evening. Then there was the disagreement among the weather equipment and the continued anomalous readings from the secondary temperature sensors, making for an interesting night even before we got to recommissioning a visiting instrument. During a short sucker hole after 0300, I decided to open (humidity was either 88%, 62%, or 97% depending on the source), just so that we could see very briefly how things were with the instrument. We quickly found that the focus zeropoint had not changed, the pointing was acceptable and the basic instrument orientation was the same as its last visit. We tried for an instrument block and managed a 4-point grid, but only got 3 very roughly-estimated points on a ring before the clouds moved in. The ring should probably be remeasured, since there was some evidence that the center of rotation was off. When we closed due to clouds after the attempted instrument block, there were radar echoes showing precipitation heading our way. The rain sensor went off at 04:20. ------- FAILURE LOG ------- PROG INST FAILURE MODE TIME (SEDFNVOG) TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- 19:35 disslit -150 1.5 03:08 cormass -50(796) 139 71 5.7/6.2 111 13 K 2.0?? ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 50 32 2 252 (WSW) mstly cldy none 17:01 48 32 1 200 (SSW) ptly cldy none 18:01 47 32 0 244 (WSW) ptly cldy none 19:01 45 32 3 358 (N) ptly cldy none 20:01 43 32 11 84 (E) ptly cldy none 21:01 42 31 8 89 (E) mstly cldy none 22:01 42 32 10 81 (E) mstly cldy none 23:01 42 32 11 89 (E) mstly cldy none 00:01 42 39 10 82 (E) mstly cldy none 01:01 42 40 6 103 (ESE) mstly cldy none 02:01 42 40 11 83 (E) mstly cldy none 03:01 43 39 14 110 (ESE) ptly cldy none 04:01 43 39 11 125 (SE) cloudy lt rain 05:01 43 40 16 161 (SSE) cloudy lt rain 06:01 41 40 16 127 (SE) cloudy rain 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 Telescope drives operational. Current Remark version: 2.85b Current TCC version: 2.7.3.2 Current TUI version: TUI 1.0.1