Date: Tue, 2 Mar 1999 06:34:00 -0700
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 990301
                           MONDAY MARCH 1, 1999
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   The enclosure was opened at about 18:00.  I set up on the meridian at
the equator.  High clouds combined with the full moon made it difficult to
see stars.  Between 19:30 and 20:00 the dust counts rose to the point where
we had to close.  Pat Waddell, Russell Owen, Larry Carey, and I were on
hand for tonight's observing, ( Russell and Larry for the first part of the
night ).
   A couple things happened while trying to close.  The first was that the
altitude stopped short of the destination in a move to position ( somewhere
in the vacinity of 23 deg ).  An amp reset didn't fix the problem ( and all
amplifier leds were green ).  However the windscreen was still active and I
didn't want to spend a lot of time debugging with the dust count over the
limit, so I moved the altitude the rest of the way to park by hand, with
the windscreen following.  A check of altitude motion as soon as the
telescope was safely in the enclosure showed everything working fine.  I
have no explanation for the stopping of motion during the move to position
and the lack of recovery.
   As I was moving the altitude down at a rate faster than normal computer
control ( maybe .5 to 1.0 deg/sec ), I was stopped at 15 deg because the 15
deg stop hadn't moved out of the way by the time I reached it.  I had to
move back up, and then it retracted and I could proceed down.  Glenn tells
me that a flow restrictor was placed in line with the 15 deg stop to keep
it from slamming.  Maybe it is a bit too restrictive?
   Dust and clouds prevented us reopening until 23:40.  After that we had a
productive night under clear or mostly clear skies.  We had to essentially
start from scratch on our primary collimation since work was done and the
primary moved during the day.  Fortunately we ended up with similar values
to last night.
        setmir:  0 -15.6 6.3 342 854
        galil: 5627 -2872  -154  787  3841  3841
   With about an hour left we tried running the astigmatism corrector.  We
only got to look at one star before we stopped for the night, and it seemed
to indicate that we may have applied the correction with the reverse sign
needed ( possibly because we used an image from the opposite side of focus
from which we thought it was ).
   At 05:00 Angela Prosapio and Glenn Federwitz arrived and they along with
Pat and I, removed the engineering camera in preparation for work to be
done during the day.
    Note: There is still a clank of one of the rods inside the windscreen
when moving down in altitude between about 10 and 15 degrees after having
been above 45 deg.  I don't know if something needs to be tightened, or if
this is normal behavior.
    End of night telescope status was with no instrument mounted,
turnbuckled to the windscreen, counterweights fully down, and the primary
covered with Tyvek, enclosure off.
                                    Dan