Date: Wed, 9 Jun 1999 05:33:41 -0600
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 990608 ( MJD 51339 )
                          TUESDAY JUNE 8, 1999
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
    Observering team:   Dan Long                (APO)
                        Francisco Castander     (UC)
                        Aronne Merrelli         (CMU)
   Tonight was a spectroscopy night... and what a night it was!  We took
three half plates worth of spectra.  That's over 900!!!
    Time         Plate        Coords             Calib offsets     exposures
22:30 - 23:30:   133 (coma)  194.85,    27.95     unrecorded      3  20 min
00:10 - 01:45:   135 (eq)    248.6929, 0.02379   0.,.001,-.02      4  20 min
02:40 - 04:20:   136 (eq)    245.8221, -.03507   .0005,-.001,0     4  20 min
   The SOP a.k.a. "evil" guider did a wonderful job, and the quickness of
setup was also much appreciated in this three plate night.  Best focus
varied between about -275 and -400 throughout the night.
   Telescope pointing was good enough that guide stars could be seen in at
least some of the fibers just slewing directly to the target with no FK5
correction.
   There were no real problems in instrument change.  The swaps of
cartridges were done under 20 minutes each time.  However, the azimuth and
rotator axes hum loudly when moving at slew speeds and the altitude is near
zenith.  The azimuth oscillation can be damped out by engaging the altitude
brake.  Both oscillations stop when the axis reaches its destination.
   Guider images look strange as one goes out of focus, going quickly to a
double peaked peanut shape.  The problem with the secondary being well out
of collimation in translation ( found earlier in the day ) is a likely
cause.
                                MIRROR NUMBERS
   Primary:
   setmir:  0   3.9   -2.3   -128.1   -213.5
   galil:   4350 -1750   0 -16300  -11550  -11450
   linear gauges
        1.9325
        0.5555
        0.5575
        0.4220
        1.8845
        0.3840
   Secondary:  30 deg El.  Spectro as instrument
      SecOrient= 3481.8, -229.8, -100.0, -50.0, 270.6
      galil:  4437361.,4178301.,4542511.,-21479.,-27205
   The red camera began warming at around 03:30, so I refilled the 10 liter
dewar at that time rather than at dawn as I had planned.  It was close
enough to dawn, that I did not fill it again at 05:00.  It should make it
to at least noon on this fill.
   The cartridge and corrector were removed at the end of the night and
left on the cart in the shed.  The telescope can't quite be balanced empty
and remains a little top heavy.  Just be aware it may drift down if out of
closed loop in altitude.  The telescope was closed up at 05:20.
                                WEATHER
   Weather tonight was clear all night.  Winds were light southwesterly
until about 0:00, then switched abruptly to the southeast for the rest of
the night. temperatures were about 18 C before midnight and about 10 C
after.  The dewpoint depression was up to 34C until the wind changed
direction and ranged between 8 and 12 C the rest of the night.  Dust counts
ranged from 1500 to about 2500.
   Prior to the windshift seeing was in the 1.2 to 1.5 arcsecond range.
Afterwards it was in the 2 to 3 arcsecond range.
                                  Dan