Date: Mon, 15 Mar 1999 06:23:50 -0700
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 990314
                          SUNDAY MARCH 14, 1999
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   The enclosure was rolled off at about 18:30 after having been open and
ventillating for about an hour.  It had been open all day until about
15:00.
   Skies tonight were variably cloudy with cirrus from nearly clear to
partly cloudy.  Winds were light out of the south to south east which made
for variable seeing from a little under 1.5 arcseconds to more than 4
arcseconds at times.  It was moderately dusty for the first half of the
night with counts between 2000 and 3000 counts per tenth cubic foot.
Shortly after midnight they jumped over 4000 so we closed.  We reopened
about an hour later.
   The night was spent set up looking at the southern equatorial strip.
The non-photometric conditions and poor seeing prevented getting any
science data.
   The telescope was well behaved tonight.  I noticed that altitude and
azimuth position was repeatable to about 10 arcseconds in the two times I
set up on the equator and meridian tonight.  An interesting thing is that
the position at which the azimuth stow light comes on varies by +/- 30
arcminutes.  Until tonight I had attributed that to the azimuth encoder
loosing position by about that much in a 120 deg slew, but that isn't
happening.  I don't understand what is causing the variability in stow
position.  The rotator is still having trouble making slow moves, but is a
known problem.  The servo parameters can be tuned for high or slow speed
motion, but not both at the moment.  It is currently set for high speed
motion so large moves don't take forever.
   The telescope was left out for Bill Boroski and Paul Czarapata who
arrived to take over at about 06:15.
                                  Dan