Date: Mon, 14 Sep 1998 04:42:01 -0600
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 980913
                        SATURDAY SEPTEMBER 13, 1998
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
   Enclosure was rolled off at about 18:30.  From then until it got dark
enough to line up on Polaris, some work was done characterizing windscreen
motion with Claudio Rivetta.
   The weather tonight was marked by variable mid-level cloudiness.
Otherwise it was a nice night with mild temperatures and light winds.
   We fought clouds most of the night, but got the primary in a good
collimation position.  The numbers for the primary were as follows.
Y-trans 1.9mm
x-trans 1.7mm
x-tilt  -34.8 arcseconds ( down )
y-tilt   31 arcseconds   ( to the left )
or in galil terms
6891.,-6112.,622.,18803.,46071.,46068.
   Best focus was achieved with the secondary at -1160, and fwhm was about
1.5 arcseconds.  The primary's astigmatism showed quite clearly at these
collimation settings.
Clouds got thick enough by 04:00 that we had to close for the night.
   There were some small glitches in telescope control.  A couple times
after the telescope had been tracking in azimuth for a while at a rate of a
few counts per second, changes in the tracking rate were ignored.  The new
rate was shown in the menu as it should but the axis would continue its
former rate.  If the axis was stopped, a new rate would then be accepted.
   Again tonight on two occasions when the stow position switches freed
themselves from their forced closed state, the altitude stopped moving.  It
will be a relief when the logic is fixed such that the altitude can be
moved with these switches open ( and above 20 degrees of course ).
   Something we didn't understand concerning the change in parameters using
setmir on the primary happened as well.  For some reason the x-translation
parameters showed a change of about 400 microns each time we changed the
y-tilt by 10 arcseconds.  An excerpt of the output from setmir commands is
listed below  ( arrowed terms ).
orientation: piston (um), x-y tilt (") and x-y translation (um)
0 40 0 0 0
moving Prim actuators to:
   1967.44477230846
  -1883.61098607513
   1316.38901392487
  -12374.0470475203
  -8798.55812238879   <---
  -8798.55812238879   <---
orientation: piston (um), x-y tilt (") and x-y translation (um)
0 40 -20 0 0
moving Prim actuators to:
   1967.46335137938
  -743.623365914915
   176.438514676178
  -12374.0470052650
  -9597.93359908303   <---
  -9599.44619834876   <---
orientation: piston (um), x-y tilt (") and x-y translation (um)
0 40 -30 0 0
moving Prim actuators to:
   1967.48657533224
  -173.615639118943
  -393.522811265895
  -12374.0469522746
  -9997.62132476170   <---
  -9999.89024430829   <---
orientation: piston (um), x-y tilt (") and x-y translation (um)
0 40 -40 0 0
moving Prim actuators to:
   1967.51908882055
   396.401364193298
  -963.474852925865
  -12374.0468782708
  -10397.3090407475   <---
  -10400.3342943319   <---
                                   Dan