Date: Tue, 7 Sep 1999 05:50:33 -0600
From: Dan Long
Subject: 2.5m obslog 990906 ( MJD 51429 )
                           MONDAY SEPTEMBER 6, 1999
                      APACHE POINT OBSERVATORY SDSS 2.5m
                               OBSERVING  LOG
     Observering team:   Dan Long                (APO)
			Stephanie Snedden	(APO)
			Jim Annis		(FNAL)
                         Francisco Castander     (UC)
                         David Schlegel          (PU)
			Bob Nichol		(CMU)
    Tonight the engineering camera was again on the telescope.  The
plan was to check the collimation of the primary, get a small
pointing model, then put on the imaging camera and take some
equatorial and off equatorial scans.
    We were open briefly between about 19:30 and 20:30, between when
the afternoon storm clouds cleared, and the humidity rose too high
after sunset.  The rest of the night was either too humid, too
cloudy, too rainy, or all three.
    While we were open, we did manage to run the telescope in altitude
and see how the mirror support system reacted.  It behaved.  The
pressures stayed where they should at about +42, and -10 PSI.  No
oscillations were observed.  See below for mig values at 15 deg and
87 deg elevation.  The primary returned to its low elevation values
after going to the zenith and wasn't very much different at zenith in
any case.  The secondary didn't really return to its previous
location when the altitude was returned to 15 degrees.  Is this a
cause for concern?
                                 MIRROR NUMBERS
    Primary:
    setmir:  0  -15.6   15.6   854   854
    galil:   5650, -3400,  400,  800,  21850,  21250
    linear gauges
      15		  87		15 again
  1 = 1.9290	1.9285		1.9290
  2 = 0.5595	0.5610		0.5595
  3 = 0.5560	0.5570		0.5560
  5 = 1.9245	1.9245		1.9235
  6 = 0.4255	0.4245		0.4245
  4 = 4.0630	3.9950		4.0470
  7 = -3.0420	-3.1190		-3.0580
  8 = 3.5440	3.4760		3.5290
    Secondary:    Engcam as instrument
       SecOrient: NA
       galil:  -3058550, -2973800, -3038200,  9900,  11500
    Bob Nichol made a check of the flat field lamps tonight, and
reported that the two banks currently connected worked.  He did
mention that the Ne lamps seemed to be a little out of adjustment,
needing some amount of rotation to put the illumination pattern fully
on the flat field screen.
    Twice during the night, SP2 stopped responding.  In both cases one
of the power supplies ( the one on the right looking down on them )
showed an error on the +5 V logic.  Power cycling cleared the problem
in both cases.
    TPM data was logged for most of the night using the "start
data990906" command.
    Nitrogen notes:  Both spectrographs were filled between 17:30 and
18:00 and again at about 03:00.  The 180 L dewar for the imager was
changed at about 05:30.
                                 WEATHER
    Weather tonight was mostly clear at sunset.  The humidity rose
above the limit about an hour later.  Clouds moved in about an hour
after that.  At about 22:00 it began raining.  It rained on and off
until about midnight.  It was partly to mostly cloudy with high
humidity for the rest of the night.  Temperatures were in the lower
50s most of the night.  Winds were out of the SE most of the night.
                                   Dan