Apache Point Observatory 3.5m Telescope Night Log Saturday, September 19, 2026 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- GS03 T.Henry J.Davidson GS03 T.Henry J.Davidson ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- GS03 DSSI 19:12 01:56 GS03 DSSI 03:34 04:20 GS03 DSSI 05:26 06:00 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- GS03/R 19:12 01:10 0 0 0 0 0.3 5.7 0 0 GS03/R 01:10 06:42 3.3 0 0 0 2.2 0.0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: H.Abbot Clear skies through A-half with rain cloud coming in around 0200. They passed and we were able to open again around 0330. Small speck of rain followed up around 0420. Sky cleared up again at 0526, but then humidity spiked forcing closure around 0600. Echelle ThAr PSU needed a jolt of percussive maintenance to get the IOL measurement in the afternoon. Recieved this error around the start of morning twilight: "Slew failed: Sub-command(s) failed: DRIFT: Cancelled while queued by new command 'DRIFT'; DRIFT: Cancelled while queued by new command 'DRIFT'; DRIFT: Cancelled while queued by new command 'DRIFT'" Reslewing to target resolved the issue. ------- 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 -------------------------------------------------------------------------- 19:31 dssi 452( 1590) -98 73 15.3 17.9 17.2 17.4 16.0 692nm 1.00 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 63 49 1 251 (WSW) 2551 mstly clr none 17:00 67 51 11 249 (WSW) 2248 clear none 18:00 66 48 9 269 (W) 1967 clear none 19:00 61 47 1 254 (WSW) 2394 clear none 20:00 60 45 2 293 (WNW) 1977 clear none 21:00 60 46 6 260 (W) 1855 clear none 22:00 59 47 5 260 (W) 1912 clear none 23:00 59 47 8 226 (SW) 1776 clear none 00:00 59 45 6 264 (W) 1214 clear none 01:00 59 45 6 277 (W) 985 mstly clr none 02:00 59 45 12 274 (W) 1047 cloudy none 03:00 55 48 8 186 (S) 1553 ptly cldy none 04:00 54 48 8 184 (S) mstly clr none 05:00 54 48 9 201 (SSW) ptly cldy none 06:00 52 49 9 189 (S) clear humid 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