Subject: 3.5m Night Log 20230903
From: mcmillan@apo.nmsu.edu
Date: Mon,  4 Sep 2023 13:24:00 +0000 (UTC)
                      Apache Point Observatory
                      3.5m Telescope Night Log
                      Sunday, September 03, 2023
PROG  PI ASTRONOMER      OBSERVER(S)
--------------------------------------------------------------------
GS03  T.Henry           J.Davidson,R.Wilson,E.Horch
                         ON-SKY
PROG  INSTRUMENT     START   FINISH
--------------------------------------------------------------------
GS03  DSSI           20:00    06:30
   PROG       SCHEDULED      WEATH     EQUIP     OBS     NOT USED
 I/ROW/DTN  START  FINISH   D    B    D    B    D    B    D    B
-----------------------------------------------------------------
GS03/R      19:34  06:31    0    0    0    0   2.2  8.7   0    0
note: scheduled times listed include instrument change time
              ------------- ACTIVITY LOG --------------
Observing Specialist: R.McMillan
We had intermittent high clouds with clear patches between.  Good seeing at the start of the night got worse during the middle period, and then good again towards dawn.  The measurement of 1.2 in the focus log was really a best-case; seeing around that time mostly looked a lot worse.
We saw tracking oscillations in both az and alt at various positions around the sky.  The alt oscillations in particular looked worse on the instrument than on the telescope telemetry, and were seen both in the east with upward tracking and in the west with downward tracking.  No motion errors during slews, but there were some cases of azimuth showing larger than usual fiducial corrections.
Here were some spot-checks of the dust counts, since a faulty dewpoint reading caused the regular dust counters to turn off:
18:40 569
21:00 592
01:00 820
03:00 769
                    ------- 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
--------------------------------------------------------------------------
 19:15 dssi   582( 2232) 104  62  17.8 20.2 19.6 19.4 19.0   692  0.78
 23:37 dssi   532( 2055)  -1  45  17.7 17.3 17.8 17.0 17.4   692  1.20
               ------------- WEATHER LOG ----------------
                                   Wind                      Precip.or
     Time   Temp F Dewp F  MPH  Direction    Dust    Sky    Conditions
    ------------------------------------------------------------------
     16:00    69    41     12   279    (W)         ptly cldy   none
     17:00    73    42      7   260    (W)         ptly cldy   none
     18:00    71    43      6   265    (W)         ptly cldy   none
     19:00    67    42      6   258  (WSW)        mstly clr    none
     20:00    64    41      7   197  (SSW)        mstly clr    none
     21:00    64    41     10   203  (SSW)         ptly cldy   none
     22:00    63    40     14   201  (SSW)        mstly clr    none
     23:00    64    40      9   208  (SSW)         ptly cldy   none
     00:00    64    40     10   198  (SSW)        mstly clr    none
     01:00    64    38     11   213  (SSW)         ptly cldy   none
     02:00    64    42     10   261    (W)        mstly clr    none
     03:00    62    41     11   242  (WSW)        mstly clr    none
     04:00    61    39     17   208  (SSW)        mstly clr    none
     05:00    61    36     11   216   (SW)           clear     none
     06:00    61    40      6   234   (SW)           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.
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