Date: Wed, 14 Oct 1998 06:59:00 -0600
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 981013
                         TUESDAY OCTOBER 13, 1998
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   The enclosure was rolled off at 18:40 to mostly clear skies.  The skies
were variably cloudy all night, and were thickest between 01:00 and 03:00.
Seeing varied between about 1.0 and 1.5 arcseconds.
   The first part of the night Pat and I spent verifying the primary tilts
and translations put in at the end of last night.  This was done on the
equator.  The values proved to give very symmetric images.  The numbers
were
                0 -7.2 21.1 1150 400
   Next we went to just west of the zenith and tried tracking stars just
coming off the zenith.  This worked well.  It was possible to track even
longer here than at the equator ( about 10 degrees .vs. 4 degrees ).  We
obtained a new set of primary parameters here.
                0 -6.3 30.7 1675 350
   It was decided that the primary translation values obtained near zenith
should remain unchanged for other elevations.  Thus when we went back to
the equator, and then Polaris, we applied only tilts to make the donuts
symmetric.  For both Polaris and the equator an x-tilt of about -20
arcseconds from the nominal value at zenith worked very well.
                0 -26.3 30.7 1675 350
   The telescope was closed at 06:45.  We had no problems with the
telescope tonight.
                                Dan