Date: Wed, 01 Sep 1999 04:51:31 -0600
From: "s. a. snedden"
Subject: 2.5m obslog 990831 (MJD 51423)
                          Tuesday August 31, 1999
                              (MJD 51423)
                   Apache Point Observatory SDSS 2.5m
                           Observing Log
Tonight's Observing Team:
                Ellyne Kinney (APO)
                Jeffrey Hayes (APO)
                Stephanie Snedden (APO)
                Connie Rockosi (UC)
Tonight's plan included training the observers in the care and feeding
of DIMM, testing the MCP some more and collimating the primary.
The DIMM is operational, and Karen Loomis showed Ellyne, Jeff & Steph
how to set it up, so it should be operational for the dark run.
Tonight's seeing averaged around 1.3" FWHM.
Karen also gave us a bit of advice to pass along to everyone coming here
for the dark run, driving cars with automatic headlights. It is possible
to override the headlights by pulling applying the parking brake very
lightly...if it's a hand brake, pull up just a little...not even to the
first notch, and the headlights should go off. The observers request
that you give this a try while approaching the observatory at night.
Also note that a knife-blade type on-off switch has been installed below
the windbaffle electronics, so the wind baffle circuit breaker can now
be left on.
Set-up tonight was uneventful, with the exception that we had to power
cycle the rotator Glentek after an abort that we could not recover from
with the MCP menu. This occurred while setting the fiducials. The
rotator behaved normally after this.
We then did some test slews and offsets with the TCC, and in general,
were succesful. We do have a question about whether or not large rotator
offsets are possible, or if we are limited to small angles. When we
tried an "offset calib 0,0,theta" where theta is some angle larger than
a degree, the rotator moved about 1 degree, then stopped. Should we be
able to do large rotator changes with the offset command? If the answer
is "yes", then it appears to be failing.
The rest of the night was a rather dismal failure. We tried slewing to
an fk5 star in order to take images for Connie to collimate the primary
with. When we tried a "gcam doread" command, at first we got:
    GCamReply Camera not responding; ppk error:Error code=116
We checked fibers and connections, power cycled the engineering camera
and the guider Mac in various combinations and permutations and
eventually were able to communicate with the camera. We then took
another image and the display showed only values typical of a bias
frame. We tried longer exposures and the "flashlight test" to see if we
were getting some signal and that the shutter was working, but saw no
change. Eventually we realized that there was a narrow strip at the top
and bottom of the frame that read expected values (higher values for
longer exposures, or more photons) but the rest of the frame just showed
typical bias values. We tried a "gcam initialize" command and the small
strip of "correct" values at the top of the frame changed to cover about
the top 1/4 of the frame. We believe the values set in the instrument
block to be correct, and have saved them to a file on galileo in the
visitor1 directory called "temp.txt" if anyone would like to take a look
at them. A good image to look at to see what we are talking about is
gimg0011.fits on sdsshost in the /data/spectro/guider directory. (Taken
on September 1). Power cycling the camera did not change anything, and I
am beginning to wonder if we have a timing/readout electronics problem
with the CCD.
Since Connie had to get some much-needed sleep, we called it quits at
03:00.
**Day crew please note that the cover was left off the telescope (stowed
in the support building) and will need to be put back on before any
construction work.
The weather ranged from partly to mostly cloudy. Temp stayed around 60
deg F. The wind was from the SSE at about 20 mph with gusts ranging from
25 to 30 mph. Dust counts rose from 500 too almost 1000 while we
observed.
Steph reporting for Ellyne, Jeff & Steph