Apache Point Observatory 3.5m Telescope Night Log Tuesday, December 23, 2025 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- AP01 S.Merkowitz T.Sutherland UW02 P.Yoachim D.Meng,Z.Xu BY03 M.Joner M.Joner,B.Boizelle OU02 Sameer Sameer,C.Gray ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- AP01 APOLLO 17:21 18:10 UW02 KOSMOS 18:16 21:11 BY03 KOSMOS 21:13 00:07 OU02 KOSMOS 01:12 02:30 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- AP01/W 17:11 18:11 0 0 0 0 0.0 1.0 0 0 UW02/R 18:11 21:10 0 0 0 0 0.6 2.4 0 0 BY03/R 21:10 00:10 0 0 0 0 3.0 0.0 0 0 OU02/R 00:10 06:54 5.4 0 0 0 1.3 0.0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: A.Townsend At the start of the night ATUI was giving Torrie some troubles, and we probably only got one reflector due to the clouds. We also had a point where both Torrie (offsite) and I (obsA onsite) had TUI freeze up for about 30s before it came back, and then when Torrie slewed after that the Az value was a little off and said motor buffer empty in the status window. After reslewing everything looked ok. I also had all of the local APO websites stop loading as well as the kcam slitviewer image failed to load on obsA at about 03:25; they all came back when I unplugged the 10.75 cable to see if that might be related to the problem. I plugged it back into obsA this morning, and I can still load the APO pages so that seems to have been an odd hiccup. We had amazing seeing but we also had clouds all night. They were thin enough during A-half to observe through, but we weren't getting any photons after 02:30 from OU02's faint targets and so we paused for cals, and things never cleared up enough to get back on sky. ------- 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 -------------------------------------------------------------------------- 17:32 APOLLO 450( 1928) 281 33 10.4 12.1 11.5 11.5 10.3 530 1.50 18:29 kosmos 535( 1135) 320 53 10.1 10.5 10.9 10.1 10.1 -- 0.65 21:24 khigh 500( 1041) 249 70 10.4 9.5 10.1 9.4 9.9 -- 0.54 00:25 kosmos 440( 944) 149 65 9.3 8.7 9.3 8.6 8.9 -- 0.60 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 53 13 5 254 (WSW) 636 ptly cldy none 17:00 50 14 3 195 (SSW) 586 ptly cldy none 18:00 51 12 8 241 (WSW) 682 ptly cldy none 19:00 50 12 8 217 (SW) 557 ptly cldy none 20:00 50 13 9 183 (S) 432 ptly cldy none 21:00 50 8 10 188 (S) 401 ptly cldy none 22:00 50 12 10 187 (S) 544 ptly cldy none 23:00 50 13 16 203 (SSW) 577 ptly cldy none 00:00 49 14 16 183 (S) 656 ptly cldy none 01:00 49 13 12 184 (S) 637 mstly cldy none 02:00 49 13 14 188 (S) 682 cloudy none 03:00 48 17 6 183 (S) 845 cloudy none 04:00 48 15 12 206 (SSW) 770 cloudy none 05:00 49 17 7 189 (S) 928 mstly cldy none 06:00 47 18 9 194 (SSW) 1015 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: 3.1.8