From: "S. A. Snedden"
Subject: 2.5-m Obs Log 03/22/00  (MJD 51626)
Date: Thu, 23 Mar 2000 00:06:32 -0700
                        WEDNESDAY MARCH 22, 2000
                     APACHE POINT OBSERVATORY SDSS 2.5M
                               OBSERVING LOG
                                (MJD 51626)
OBSERVING TEAM:
===============
                 Dan Long                 (APO)
                 Steph Snedden       (APO)
Visitors:
                 Robert Lupton          (PU)
                 Peregrine McGehee (LANL)
                 Alan Uomoto            (JHU)
THE PLAN:
=========
Shakedown tests, following the observers' shakedown document (developed at
the end of January).
SYNOPSIS FOR NIGHT:
===================
Cloudy with snow that was heavy at times. The observers left at about 19:00,
(barely) before the roads became impassable. We believe the late shift will
also not come in due to road conditions. It is very unlikely we would be
able to open at all tonight. A few tests were completed on the alt drive
motors, and some biases were taken.
TELESCOPE STATUS:
=================
The telescope was left parked at 30 deg. altitude with corrector and
cartridge 3 on. Counterweights are at 320.
DIMM:
-----
DIMM seeing not available -- clouds.
INTERLOCKS:
-----------
None bypassed.
SOFTWARE USED:
--------------
                IOP/SOP: v3_11_5
                Watcher: v2_8_0
                MCP: v2_8_1
WEATHER SYNOPSIS (see below for hourly data):
=============================================
Clouds. Snow.
GENERAL COMMENTS (see Problems below for details):
==================================================
A few imager and spectro biases were taken before we fled the snow. See the
Data Acquisition section for the run/frame numbers.
Per the morning phonecon, some tests were run on the alt drive motors. We
made short slews of 5 degrees at a speed of 50000, at high, middle and low
altitudes. We moved in both increasing and decreasing altitude directions.
After reaching the destination altitude, we waited a bit to see whether the
drive voltages would change (hold V). The results:
Altitude        V (volts)        Hold V (volts)
--------        ---------        --------------
90-85 deg    -250            -230
85-90            2300           2250
90-85            -300            -250
85-90            2350            2300
45-40 deg    -1800          -1600
40-45            1000            920
45-40            -1650            -1510
40-45            1000            1000
10-5 deg        -2500          -2310
5-10                350            330
10-5                -2300        -2200
5-10                450            390
Note that the "hold voltages" do not drop significantly from the values
while moving in altitude.
We next set CW 1 to a value of 370 and left the others at 300. This balanced
the drive voltage at low altitude. We then checked the voltage at different
altitudes:
10-5 deg        -1400
5-10                1400
45-40 deg        -400
40-45                2400
90-85 deg        0
85-90                2600
Finally, as a check that it doesn't matter if we move just the one CW, we
moved all four to 317. This should give the same results as the previous
ones:
10-5 deg           -1450
5-10                   1400
45-40 deg         -1000
40-45                 1900
90-85                -150
85-90                2500
These values are consistent with the previous set.
French is correct that the most symmetrical balance condition varies from
absolute values of about 300 to about 3000. Dan believes we are dealing with
both a top/bottom and front/back out-of-balance condition, and that we can
improve conditions by balancing voltage at low altitude, then going to high
altitude and adding or removing bolt-on counterweights. We suggest we not
spend too much time on this if the movable counterweights are to be replaced
in the near future, requiring rebalancing at that time.
While these values were recorded by taking a visual average from the new MCP
Menu, Peregrine was recording the values using his real time monitor. We
noticed that the real time monitor and Menu values were quite different, and
Peregrine and Robert were looking into this when we left.
DATA ACQUISITION (see IOP/SOP output below):
===========================================
          IMAGING:
          --------
Run 1278, bias, 57 frames
Run 1279, bias, 55 frames
          SPECTROSCOPY:
          -------------
Frame 3158, bias
Frame 3159, bias
No tapes are to be shipped...they can be recycled.
MIRROR NUMBERS
==============
Not available.
                             FOCUS LOG
                             ---------
Time   Inst     Focus(piston)     Az   El    Temp  Dir  MPH  filter  FWHM "
Not available.
LN2 SCHEDULE:
=============
Imager dewar not changed. It was more than half full when we left at 19:00.
Spectro dewars filled at 18:30.
WEATHER DATA:
=============
                                 Wind
     Time   Temp F Dewp F  MPH   Direction    Dust      Sky     Precip.
     16:01    29    29      8    11  (N)      114    Cloudy    Snow
     17:01    25    25     12    25  (NNE)    400    Cloudy    Snow
     18:01    25    24      1   213  (SSW)    880
     19:01    27    26      6   180  (S)     1012
     20:01    26    25      1   268  (W)      736
     21:01    21    20      9   269  (W)     1030
     22:01    21    17     14   263  (W)     1096
     23:01    21    20      1   275  (W)      958
pcl=partly cloudy, mcl=mostly cloudy
TAPES WRITTEN:
==============
Tapes are to be recycled. Do not ship.
PROBLEMS IN DETAIL:
===================
DATA LOGS FROM IOP/SOP:
=======================
n/a yet