Apache Point Observatory
                      3.5m Telescope Night Log
                      Tuesday, February 10, 2026

PROG  PI ASTRONOMER      OBSERVER(S) 
--------------------------------------------------------------------
CU01  Z.Berta-Thompson  A.Stephens            
BY01  D.Stephens        D.Stephens+class      
AP01  S.Merkowitz       R.McMillan            

                         ON-SKY
PROG  INSTRUMENT     START   FINISH
--------------------------------------------------------------------
CU01  KOSMOS         18:35   20:53   
BY01  KOSMOS         --:--   --:--
AP01  APOLLO         05:52   06:25

   PROG       SCHEDULED      WEATH     EQUIP     OBS     NOT USED
 I/ROW/DTN  START  FINISH   D    B    D    B    D    B    D    B
-----------------------------------------------------------------
CU01/R      17:53  00:10  4.0    0    0    0   2.3  0.0   0    0
BY01/O      00:10  05:41  2.4  3.1    0    0   0.0  0.0   0    0
AP01/W      05:41  06:41    0  0.5    0    0   0.0  0.5   0    0

note: scheduled times listed include instrument change time

              ------------- ACTIVITY LOG --------------
Observing Specialist: H.Abbot,A.Townsend

Thin clouds at start of night with rain on the horizon. Opened for observations for 2.3 hours before the clouds got too thick to observe through. Thick cloud continued for the rest of the night.

CU01 was doing cals until 18:30, weather was marginal but we decided to try get on sky while the clouds were light. Clouds got thicker around 20:30, and eventually we closed up at 20:53 as there was not enough signal in the exposures to warrant staying open.

BY01 was completely clouded out. Instead, the class was trained on KOSMOS cals. Clouds retreated at 05:00, but humidity remained high until AP01. Managed o get a couple photons back from the moon, but was soon clouded out again.


                    ------- 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
--------------------------------------------------------------------------
 19:01 kosmos     411(  788) -13  57   4.7  5.8  6.3  5.7  4.8   --   0.70
 05:56 APOLLO     600( 1675)  33  35   3.1  3.7  5.0  3.7  3.4   530  1.40

               ------------- WEATHER LOG ----------------

                                   Wind                      Precip.or
     Time   Temp F Dewp F  MPH  Direction    Dust    Sky    Conditions
    ------------------------------------------------------------------
     16:00    42    33      3   131   (SE)         ptly cldy   none 
     17:00    45    31      6   225   (SW)    555  ptly cldy   none 
     18:00    40    32      3   120  (ESE)         ptly cldy   none 
     19:00    41    32      6   186    (S)         ptly cldy   none 
     20:00    40    32      7   183    (S)        mstly cldy   none 
     21:00    40    32      6   180    (S)          cloudy     none 
     22:00    41    32      7   190    (S)          cloudy     none 
     23:00    41    32      5   197  (SSW)          cloudy     none 
     00:00    41    32      7   194  (SSW)          cloudy     none 
     01:00    40    32      8   191    (S)          cloudy     none 
     02:00    40    32      8   179    (S)          cloudy     none 
     03:00    40    32     11   182    (S)          cloudy     none 
     04:00    39    32      9   183    (S)          cloudy     none 
     05:00    38    30      3   177    (S)         ptly cldy   none 
     06:00    39    31      5   187    (S)         ptly 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