Date: Sun, 28 Feb 1999 05:17:29 -0700
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 990227
                        SATURDAY FEBRUARY 27, 1999
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   The telescope was opened at about 17:00 today.  The engineering camera
was mounted, and the telescope balanced.  The counterweight settings are
around 275 for the engineering camera on the new rotator.  The "wrap-less"
connection scheme for the latches and engineering camera worked well
enough.
   As this was the first time back on the sky since the major winter
shutdown, there were a few wrinkles to be ironed out.  The air to the Az
brake and the 15 degree stop were not connected.  One interesting note;
the windscreen will not move in azimuth if the 15 degree stop isn't
physically in place, though the telescope will to the extent it can.
   Later the altitude stopped responding.  It took me a while to find it
was the old cart-not-in-the-doghouse trick which was stymieing motion.  The
cart had moved just enough to let up on the switch.  While trying to find
the problem, I discovered that the altitude was significantly out of
balance front to back as one approached zenith.  This I think can be
attributed to the new rotator motor being larger and more toward the front
of the PSS than the old one.  Fortunately moving the remaining
counterweight cover from the front of the PSS to the back got the balance
very close.
   Inspite of the first time back on the sky gremlins, we had a fairly
productive night.  The mirror systems behaved, and we got a decent start on
primary collimation.   Current primary settings are
setmir   0   -31.3   -19.6   -1069   1708
galil   6660  -1912  -2146  14475  -41584  -41584
                                Dan