Apache Point Observatory 3.5m Telescope Night Log Wednesday, May 20, 2026 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- AP02 S.Merkowitz R.McMillan,T.Sutherland WY01 M.Brotherton M.Brotherton,K.Zhang UW04 C.Orion C.Gray,D.Zhang,I.Wong ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- AP02 APOLLO --:-- --:-- WY01 KOSMOS --:-- --:-- UW04 ARCTIC 01:37 02:26 UW04 ARCTIC 04:47 05:20 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- AP02/R 20:08 23:30 0 3.4 0 0 0.0 0.0 0 0 WY01/R 23:30 01:10 0.6 1.0 0 0 0.0 0.0 0 0 UW04/R 01:10 05:52 3.3 0 0 0 1.4 0.0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: R.McMillan The first half of the night had some rain sprinkles, high dust, and heavy clouds. After midnight the dust came down and the radar dissipated, so I took a chance on a thin patch in the clouds. But it closed up again not long after we got focused, and I thought it safest to close. We gave it another try shortly before morning twilight, and that went a little bit better. But then the sky got bright, who could have predicted? ------- FAILURE LOG ------- FAILURE MODE TIME PROG INSTR TI/SHU START FINISH DESCRIPTION ---------------------------------------------------------------------- ---------------- FOCUS LOG --------------- Time Instrument Focus Az El Temp Strc Prim Sec Air filt FWHM -------------------------------------------------------------------------- 01:45 arctic 147( 799) -64 25 8.4 8.9 10.3 8.7 8.2 VR 1.45 05:06 arctic 300( 882) 30 45 8.1 7.9 8.5 7.8 7.9 VR 1.22 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 62 22 23 222 (SW) 1723 mstly cldy none 17:00 60 23 12 233 (SW) 2294 mstly cldy lt rain 18:00 57 26 22 227 (SW) 3807 cloudy lt rain 19:00 56 28 24 221 (SW) 3705 cloudy lt rain 20:00 54 27 27 215 (SW) 4577 cloudy lt rain 21:00 50 33 17 215 (SW) 17068 mstly cldy dust 22:00 48 33 14 180 (S) 28651 mstly cldy dust 23:00 47 33 16 200 (SSW) 8532 mstly cldy dust 00:00 46 33 12 174 (S) 5096 ptly cldy dust 01:00 47 32 10 182 (S) 3479 ptly cldy none 02:00 48 32 10 163 (SSE) 3193 mstly cldy none 03:00 47 32 7 172 (S) 2176 cloudy none 04:00 47 32 6 220 (SW) 1477 mstly cldy none 05:00 47 32 6 259 (W) 1476 ptly cldy 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 > 1u per 0.1 cubic feet. ---------- TELESCOPE SOFTWARE ---------- Current TCC version: 1.4.2 Current HUB version: v20171231_01 Current TUI version: 3.1.8