Apache Point Observatory 3.5m Telescope Night Log Wednesday, April 01, 2026 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- CU05 J.Bally J.Bally AP02 S.Merkowitz R.McMillan, T.Sutherland UW11 C.Chandler C.Chandler, D.Singh ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- CU05 NICFPS 21:20 22:38 AP02 APOLLO 22:40 02:05 UW11 ARCTIC 02:15 06:08 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- CU05/R 19:32 22:40 0 1.8 0 0 0.0 1.3 0 0 AP02/O 22:40 02:10 0 0 0 0 0.0 3.5 0 0 UW11/R 02:10 06:41 0 0 0 0 0.0 4.5 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: J.Dembicky Az rotator appeared to get reset today. On my first slew I started seeing fiducial errors and after my first test slew the telescope pointing in AZ was wonky. Looks like it reset the axis to 0. I slewed back to 0, which appeared to be the normal 104 position, reset the controller, then set the position to 104. I did several test slews back and forth in AZ and all seems fine now. The dome optical video feed (as well as two others) seems to be down tonight. The dome IR feed is the only one working. Russet said APOLLO video was also working, so we didn't reboot anything. at around 00:20 I noticed that the 3.5m telescope structure was a degree or more lower than all the other reported temps. it was reading just below 2C and all of the other temps were warmer than 3C. I don't believe there was any sudden temp warming outside or know why the structure temp was reading low. I have not seen this before for the structure temps. We do see it for the secondary but that is due to it cooling to the sky. The temp was changing, so it wasn't stuck. It just seems abnormal. Maybe one of the temp sensors failed skewing the average??? The rain sensor went off around 01:45 under clear skies. ------- 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 -------------------------------------------------------------------------- 21:46 NICFPS 400( 1134) -70 29 4.3 4.4 5.6 4.2 4.1 FeII-1.26 1.20 22:48 APOLLO 550( 1619) 45 37 3.5 3.6 4.5 3.7 3.7 -- 2.00 02:29 arctic 533( 816) 147 50 3.2 1.6 3.1 2.4 2.8 -- 1.62 02:32 NA2gdr 35528(35528) 147 50 3.2 1.6 3.1 2.4 2.8 clear 1.70 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 40 32 33 286 (WNW) cloudy lt rain 17:00 39 32 17 269 (W) cloudy humid 18:00 40 32 21 263 (W) cloudy humid 19:00 40 32 14 271 (W) cloudy humid 20:00 39 32 13 268 (W) mstly cldy none 21:00 39 32 19 257 (WSW) ptly cldy none 22:00 40 32 22 270 (W) clear none 23:00 38 32 21 282 (WNW) clear none 00:00 38 32 20 277 (W) clear none 01:00 38 32 22 297 (WNW) clear none 02:00 38 31 25 298 (WNW) clear none 03:00 38 28 23 303 (WNW) clear none 04:00 38 27 18 297 (WNW) 1482 clear none 05:00 38 27 19 290 (WNW) 1509 clear none 06:00 36 28 16 294 (WNW) 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 > 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