Date: Tue, 25 May 1999 05:55:50 -0600 (MDT) From: Russet McMillan Subject: 3.5m Night Log 990524 MONDAY MAY 24, 1999 APACHE POINT OBSERVATORY OBSERVING LOG ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT DATE START FINISH Strauss Fan, Strauss DIS 5/23-24 -- -- Diercks Diercks GrIm2 5/24 00:10 01:10 Kron Holden GrIM2 5/24 01:10 03:41 Turner McMillan SPIcam 5/24 04:01 04:21 INST SCHEDULED WEATH EQUIP OBS DAY NOTUSED I/RS/DN START FINISH D B D B D B USE D B PU01/R 21:39 00:10 - 2.5 - 0 - 0 0 - 0 UW01/R 00:10 01:10 - 0 - 0 - 1.0 0 - 0 UC07/R 01:10 03:51 0.3 0.3 0 0 0 2.1 0 0 0 PU03/S 03:51 04:21 0.5 - 0 - 0 - 0 0 - (note: times listed include instrument change time) ACTIVITY LOG (* means a trouble report has been issued or appended to) 1st half observing specialist: K. Gloria We had a late afternoon thunderstorm, accompanied by hail. We had a second thunderstorm at 20:00 MDT, and third at 23:00 MDT. We had a clear spell that lasted a couple hours, but remained closed due to the fluctuating humidity. PU01 did not get on the sky. 2nd half observing specialist: R. McMillan We opened at midnight when the skies cleared and the dewpoint dropped precipitously (we were suspicious at first, but other dewpoint sensors agreed, and the raindrops outside were drying quickly). We were able to get some good data, including sub-arcsecond seeing, for UW01 and UC07. The humidity rose slowly over the next few hours, then around 03:00 it became very unstable; the dewpoint was rising and falling by as much as three degrees on timescales of one minute. We closed at 03:15 due to high humidity, and remained closed until twilight. There is some question about whether the dewpoint sensor is working correctly. It was still showing a dewpoint separation of around two degrees at 03:45 when condensation developed on the rails outside and on the cloud camera. The dewpoint sensor for the pressurization fans (which has been having some trouble lately) read 98% when the other sensor read 85%. OBSERVER COMMENTS FOCUS LOG MAY 24 1999 Wind Time Inst Focus Az El #Temp Dir MPH filt FWHM " 00:20 GRIM 0(6627) 52 82 10.4/10.5 210 20 J 1.3 01:20 GRIM -30(6581) -15 75 10.3/10.0 197 19 Kshort 0.90 #First temp is air, second temp is telescope. WEATHER MAY 24 1999 Wind Time Temp F Dewp F MPH Direction Dust Sky Precip. 16:01 62 43 20 200 (SSW) 1525 mstly cldy rain/hail 17:01 54 40 16 166 (SSE) 1535 mstly cldy rain/hail 18:01 45 43 14 265 (W) 847 mstly cldy rain/hail 19:01 51 43 15 219 (SW) 1069 mstly cldy none 20:01 50 46 2 256 (WSW) 1335 mstly cldy rain 21:01 48 44 13 201 (SSW) 1047 clear none 22:01 48 43 11 221 (SW) 1679 clear none 23:01 49 44 24 218 (SW) 1389 mstly cldy rain 00:01 50 39 12 199 (SSW) 1724 clear none 01:01 51 44 10 181 (S) 1553 clear none 02:01 50 43 9 181 (S) 1714 cirrus none 03:01 48 43 7 166 (SSE) 1469 cirrus none 04:01 46 43 1 199 (SSW) 1954 clear none 05:01 45 42 2 170 (S) 2157 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: 2.5b5. Current guide software version: GIm Ctrlv3.0b17. - Karen Gloria, Russet McMillan