Date: 2018 April 17 UT
Observers: Berg, Cannata, Skillman
TO: David Gonzalez-Huerta
SA: Olga Kuhn

Moon Phase: waning cresent

Summary: 

Never opened.  Strong winds at the beginning of the night transitioning
into very thick clouds.  The clouds started to thin about one hour
before astronomical twilight and then the wind gusts picked up to an
unsafe level.  We spent a lot of time running MODS calibrations for the
previous night's observations, but there were signficant problems
running the calibrations.

Weather Conditions:
 Wind: High gusts at the beginning of the night and the end of the night
 Temp: Slowly falling through the night
 Transparency: cloudy to begin the night lasting until twilight 
 Seeing:

Minor Technical Issues:
  MODS2 Red is back, with exception of one quadrant.

Complete Programs:
  none

Calibrations:
MODS:

    The grpix flats for MODS1 and MODS2 are too high and we re-did them
    with scripts in modseng.  The scripts provided in OSURC/modscalib
    should be updated.  Same is true for r-flats for MODS2.
   
    We had problems with MODS1 blue channel.  The only good image
    numbers are 45 and 46.  (with the UG5 filter) We were not able to
    get any successful krypton+xenon or Argon grlamp exposures because
    of the problems on MODS1 blue.

    Data problems seem worse at higher count levels, but could also
    present themselves at lower count levels.  Olga has made many notes.
     
Standard Star:

Details (All Times UTC):
------------------------------------------------------------------------

01:00 - Doing MODS calibrations, closed for high winds

10:30 - starting to see a few stars on the all sky camera but also
        strong wind gusts

10:45 - Fifteen minutes to astronomical twilight. We can see the MW on
        the all sky camera.  I hate this.