Date: Mon, 26 Oct 1998 04:20:07 -0700
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 981025
                          SUNDAY OCTOBER 25, 1998
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   Tonight, much like last night, we were able to get on the sky for a
couple hours in the early part of the night.  The telescope was opened
around 19:30 to mostly clear skies.  Winds were strong from the SW at 20 -
25 MPH.  Dewpoint depression was about 4 C.  As one can tell conditions
were marginal, and the forecast was threatening a good chance of rain.
   Given that we weren't sure how long we were going to be able to stay
open, it was decided to go immediately to zenith and home the primary ( the
next operation we wanted to do last night before getting shut out by the
weather ).  After homing the primary and doing several downs/ return to
position, the sky looked good enough to set up on the equator.
   Star images looked normal again.  We continued by tweaking the rotator,
then making an adjustment of x-tilt on the primary.  The donuts looked very
symmetric in all dewars except number 1 and possibly number 2.  The primary
values are now
Primary Galil:    5000  -5150  1550  -6050  45200  45200
        setmir:      0   -6.3  30.7   1675    350
   We then proceded to take focus sweep data.  The seeing was actually not
too bad considering, at around 1.5 arcseconds.  Unfortunately clouds moved
back in and forced us to close shortly after 21:00.  We had clouds, fog,
high winds, and the forecast made good on its threat with several periods
of rain.  We did not re-open.
   Speaking of rain, the relatively heavy rain combined with SW winds of 25
to 35 MPH caused quite a bit of water to get into the enclosure ( something
in excess of 3 gal. in less than 20 minutes at one point ).  It appeared to
be coming from near the vertical beams on either side of the west door.  In
particular it was coming from the area near the side of the beam that was
furthest from the door.
   Also, the new placement for the stow indicator light will not work.  The
finderscope runs into it just as the telescope comes to zenith.  I have
removed the box and set it back on the altitude brake for now.  Since it
got bumped the finderscope will likely have to be re-aligned the next time
the engineering camera is used.
                                    Dan