Date: Fri, 11 Jun 1999 06:26:13 -0600
From: long@apo.nmsu.edu (Dan Long)
Subject: 2.5m obslog 990610 ( MJD 51341 )
                          THURSDAY JUNE 10, 1999
                     APACHE POINT OBSERVATORY SDSS 2.5m
                              OBSERVING  LOG
    Observering team:   Dan Long                (APO)
                        Jeffrey Hayes           (APO)
                        Ellyne Kinney           (APO)
                        Steph Snedden           (APO)
                        Connie Rockosi          (UC)
                        Jim Gunn                (PU)
   Tonight we adjusted the primary to eliminate coma, and did some
debugging of off equatorial scanning.
   The imager was put before twilight.  The balance is still a bit bottom
heavy when the counterweights are all the way up.
   The secondary stopped talking via the TCC at around 23:30.  The symptoms
were that a host session would not get any response, and I couldn't even
exit the session.  However, after logging out the port, I could telnet to
the controller and it behaved normally.  A TELSTOP/TELRUN did not change
things.
   After consulting with Craig, I rebooted TCCTEST.  This had the
unfortunate side effect of reconfiguring it for the 3.5m.  After this was
discovered ( and after calling poor Craig again )  I got it back to the
2.5m configuration.  The magic files reside in the MANAGER account home
directory and are called DELPORT.COM and SET25M.COM.  You run DELPORT
first, then SET25M to get the port configuration right.  I'm not sure what
Craig did to get TCCTEST to be talking to the correct terminal server.
   Once the ports were defined properly again, I could host to the
secondary and get through.  We then proceeded to collimate the primary with
the telescope parked on the equator.  In this position the secondary was at
        setmir: 1150 -205 -77 0 0
        galil: 1485000 1303900 1556400 -12000 -36000
   With the primary already set to all zeroes and relaxed at 87 deg. we
applied tilts to remove coma.  The numbers below did this.
        setmir: 0 27 -7 0 0
   The tilt and translation equivalent is then
        setmir: 0  -21.1  5.5  298.9  1152.9
        galil: 6000  -3000   -400  5600  3000  2800
        mig: ?*  .5595  .5595  .3675  1.9010  .4005
                * mig #1 was not being read properly by the tpm
   These new numbers were put into default.dat
   We then proceeded to make an off equator drift scan.  We chose 44,N.
There is a bug in the scanStripe routine.  When you ask for goDrift after
the tracking starts, it comes back with a question about the line start
rate being different and asks if it is OK to set it back to the default.
If you say no, it bails on the whole thing rather than asking for a new
value.
   Once we got going, we found the rotator to be .225 deg off from the
desired value.  I issued a calibration offset with this value.  To say this
wasn't handled well is putting it mildly.  Apparently T_TRACK dies if one
issues  the command
        offset calib 0.,0.,-.225
following the command
         track 240.09488920,81.30715723 FK5 /rotty=obj /rota=0
/ScanVelocity=(0.0024093503034054191,0.0034134000703668205) /Name="stripe
44-N" /Keep=(Boresight)
( T_TRACK died each of three times I tried it with various calib offset values )
   The axes diverge fairly quickly from the TCC requested position
afterwards ( a few degrees in each axis after about 5 minutes ).
   Another bug was discovered.  When a sizeable calib offset is in place
for an axis, issuing a track command causes that axis to immediately come
out of closed loop.  I suspect that this value is being applied instantly
rather than gradually as is now done when an offset command is issued on
its own.
   I must say that we really need to be able to tweak the rotator angle
during a drift scan without crashing anything or having to start the scan
over.  Being able to offset would also be very nice to have.  In the mean
time one can adjust rotation by changing rot_inst_ang in the inst block and
then reissuing the scanStripe command.
   The imager was taken off at the end of the night, and the telescope
closed at 05:45.
   On tap for tomorrow night is a pointing model following the day's
secondary support work.  The engineering camera should be mounted without
the corrector and the telescope balanced, fiducialed, and ready to go by
half an hour after sunset, because as long as stars show up on the chip the
engineering camera is capable of taking pointing data even in bright
twilight.
                                WEATHER
   Weather tonight was clear or mostly clear.  Winds were light
southwesterly. Temperatures were about 20 C at sunset, falling to 13 C by
dawn.  The dewpoint depression was 25 to 35 C.  Dust counts were 1000 to
1500.
                                  Dan