Apache Point Observatory 3.5m Telescope Night Log Friday, April 17, 2026 PROG PI ASTRONOMER OBSERVER(S) -------------------------------------------------------------------- GS01 D.Michael M.Davis,B.Carson UW01 P.Yoachim D.Meng,Z.Xu,Z.Liu WY01 M.Brotherton M.Brotherton,M.Myers ON-SKY PROG INSTRUMENT START FINISH -------------------------------------------------------------------- GS01 KOSMOS 17:43 00:58 UW01 KOSMOS 01:00 04:41 WY01 KOSMOS 04:42 05:48 PROG SCHEDULED WEATH EQUIP OBS NOT USED I/ROW/DTN START FINISH D B D B D B D B ----------------------------------------------------------------- GS01/R 19:43 01:10 0 0 0 0 4.9 0.6 0 0 UW01/R 01:10 04:41 0 0 0 0 3.5 0.0 0 0 WY01/R 04:41 06:21 0 0 0 0 1.7 0.0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: H.Abbot Clear night with highish dust levels, but not enough to force closure. GS01 finished early and donated the rest of their time to UW01. TUI spits out an error when setting a different instrument while telescope axes are initialised. This includes changing instrument between different KOSMOS states (klow,kosmos,khigh). Stopping axes before changing instrument avoids this. Reinitialising axes after instrument change resolves the issue. Wiki has been updated to include this info, however I imagine it belongs in a few places I'm yet to find. Process to replicate detailed in a seperate email to Bill, Cary, and Obs-specs. Example error message: 2026-04-17 23:36:15 APO.Dome 872 tcc f text="Could not start the slew: obj.axisCmdState = ArrayAxisState3(1, 1, 4); must be NotAvailable, Halted or Drifting for all axes; initializing all axes" Other than this minor issue, telescope and instruments behaved well tonight. ------- 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 -------------------------------------------------------------------------- 20:24 kosmos 522( 1095) 125 69 9.0 10.1 10.5 9.3 8.6 -- 1.18 01:11 kosmos 478( 920) -57 44 8.2 7.0 7.7 6.8 7.6 -- 1.23 ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:00 55 19 28 247 (WSW) 1397 clear none 17:00 56 18 25 255 (WSW) 1273 clear none 18:00 54 16 21 262 (W) 1519 clear none 19:00 52 17 25 267 (W) 1929 clear none 20:00 49 18 15 255 (WSW) 1537 clear none 21:00 48 18 15 264 (W) 1373 clear none 22:00 47 18 8 263 (W) 1196 clear none 23:00 47 13 13 266 (W) 1537 clear none 00:00 44 8 9 334 (NNW) 3177 clear none 01:00 46 8 10 326 (NW) 2037 clear none 02:00 46 12 0 150 (SSE) 2013 clear none 03:00 46 10 6 259 (W) 2492 clear none 04:00 45 10 8 281 (W) 2839 clear none 05:00 43 11 1 264 (W) 2712 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