Apache Point Observatory 3.5m Telescope Night Log Friday, September 18, 2026 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- UV05 Y.Zhou J.Davidson UV05 Y.Zhou J.Davidson ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- UV05 DSSI --:-- --:-- UV05 DSSI 06:00 06:41 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- UV05/R 19:14 01:10 1.2 4.7 0 0 0.0 0.0 0 0 UV05/R 01:10 06:41 4.8 0.0 0 0 0.7 0.0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: H.Abbot High dust counts through the beginning of A-half with steadily increasing humidity. Rain-bearing clouds came in by B-half and squashed any real chance of opening, right up until the end when the humidity and dust plumetted. Dust sensor going offline at around 70% humidity along with no handheld sensor made it tough to open tonight. Potentially could have opened earlier, but only had dust reading from 10pm along with vibe checks to go off of. Played it safe and stayed closed due to 80+% humidity. No telescope or instrument issues to report. ------- 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 -------------------------------------------------------------------------- 06:19 dssi 552( 1481) 150 72 13.3 13.6 15.7 13.2 12.8 692nm 0.70 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 63 52 12 194 (SSW) 4871 cloudy dust 17:00 65 49 15 224 (SW) 5527 ptly cldy dust 18:00 65 50 9 195 (SSW) 5306 ptly cldy dust 19:00 62 47 15 187 (S) 5060 mstly clr dust 20:00 60 47 13 198 (SSW) 4870 mstly clr dust 21:00 59 49 10 183 (S) 4504 mstly clr dust 22:00 59 50 14 212 (SSW) mstly clr humid 23:00 58 51 7 214 (SW) mstly clr humid 00:00 56 51 5 197 (SSW) mstly clr humid 01:00 57 51 8 181 (S) ptly cldy humid 02:00 58 50 10 184 (S) mstly cldy humid 03:00 56 51 7 212 (SSW) cloudy humid 04:00 56 50 14 200 (SSW) cloudy humid 05:00 55 50 11 210 (SSW) cloudy humid 06:00 53 44 7 193 (SSW) 1521 mstly 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: 3.2.2