Date: Sat, 22 May 1999 06:07:14 -0600 (MDT)
From: hayes@apo.nmsu.edu
Subject: 2.5 m obslog for 990521 (MJD 51320)
			Friday May 21, 1999
		Apache Point Observatory SDSS 2.5m
			     Observing Log
Observing Team:
		Jeffrey Hayes (APO)
		Ellyne Kinney (APO)
                Bob Nichol (CMU)
                Connie Rockosi (UC)
Weather:  Partly cloudy with high dust and humidity.  Winds: ~20 mph steady
and gusts up to 25 mph.  The weather was very unsettled.
On tonight's menu, we were to obtain a 30-40 point pointing model and if time
permitted, change to the cartridge for guiding tests.
We opened at about 10 pm MDT because of the weather.
We swapped the mosaic camera for the engineering camera, filled the
spectrograph dewars, and by the time this was all done, it was close to
midnight.
Before we started up the pointing model using the axis init between slews,
we did a focus sequence on the FK5 star at 228.79733, 4.9393611.  We sited
on a focus of -300.  We started the DOPTERR programme at about 1 am when
Hayes noticed lightening in the SE.  We waited for a few minutes, and noticed
lightening from due E and from the N as well.  This, with the combination of
ominous dark clouds in the SE prompted the decision to close up.  This was
done by 2 am.  We noted that although the dew point depression from the
tower was ~ 7C, we could feel condensation on metal surfaces.  At this
time the PT folks closed up as well.
Having waited out the weather again, we reopened at 2:50 am and proceeded
to obtain a 30 point pointing model.  The results are as follows: 3.1" RMS
errors using 8 co-effecients.  In the S the programme claimed to find stars,
but in fact the CCD frames were empty.
We deleted five points here: three because of the empty frame problem, and two
because they were large outliers.
The spectroscopy folks obtained a number of measures for their flexure
model, as the could take observations while we did the pointing model,
with the addition of points near the zenith.
3 last things to note.  1.While slewing the telescope back to stow position
from roughly the meridian, I noticed that the rotator was moving as well.
This was under the control of the MCP.  While moving the 121 degrees in
AZ, the rotator moved -26:16:54, and did not stop when the AZ axis reached
stow, but had to be stopped with an H.  My axis velocity was 70000 ct
2. the circular cover over the secondary mirror electronics makes an
awful lot of noise in winds of over 20 mph: it bangs into the secondary
supports with quite a vengence.  3.  the motors on the W
door are very noisy -- more so than normal.  It sounds as if they are under
strain.
We closed up at 5:30 am
Ellyne and Jeffrey