MDM Observatory 1.3m Telescope Observing Report for 2011 Jun 29

Observer(s): Jules Halpern
Institution(s): Columbia

Instrument: Templeton

Worked for 4 hours (off and on through the night)
Conditions were Non-Photometric most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   Beg: Seeing 2.0 arcsec, Cirrus, Winds Light & Variable
   Mid: Seeing 1.5 arcsec, Patchy Clouds, Winds Light & Variable
   End: Overcast, Winds Calm

Observing Summary:

At the beginning of the night, rslit was not running,
which required the TCS to be restarted.  The pointing
was lost, and it took a while to recover.  The sky was
clear start of the night, but thin clouds soon came by
and lightning could be seen in the distance.  The clouds
then became thick in patches.

The telescope cannot complete a slew.  The tracking turns off
somewhere along the way, and you need to patiently execute several
such steps to get to the target. Once, the mirror covers closed 
all by themselves.  The jumps in declination make if difficult
to come up with an observing plan that can be usefully executed.
It seems that some telescope positions or times of the night can 
be relatively free of this problem, while at other positions the
jumps come every minute or so.  When the telscope jumps,
the coordinates change in the declination display.  Bob says that
he can even see the declination jump when the telescope is just
sitting in place, not even tracking.  This seems to me to be an
important diagnostic.   So I tried it myself, and it's true:

THE TELESCOPE JUMPS IN DECLINATION EVEN WHEN IT IS NOT TRACKING!

I could see the move in the star trails as well as in the
declination display.  It moved by south by about 24 arcseconds, 
and then came back to the original position.

It has been cloudy for most of the night, so I stowed the
telescope for a while.  This action is just as difficult
as pointing.  It takes several tries to home both axes.

By 2:30am the clouds seem to have settled in, 
so I gave up the night.


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Submitted on 2011 Jun 30 [2:55:37]