TOM1 Setup Progress

[Tom Droege <tdroege@veriomail.com>]

Good progress is being made setting up TOM1.

I made two runs last night.  One was 19 images where I returned the mount 
to the starting zenith angle after each exposure.  This gives images with 
stars in different positions.  I then used this to make a set of darks 
(three of the images were darks) and flats.  These were fair.  Good enough 
to test with.

The second run tracked the sky and made 100 second exposures.  This 
produced an exposure every 154 seconds.  63 exposures were made tracking 
the sky for 2.7 hours.  There were no sudden jumps in the tracking.  There 
was a slow drift of 20' of arc per hour.  This is 0.04%.  I should be able 
to adjust this to 0.01%.

There was a drift northward of 4' or arc per hour.  I have rotated the 
mount in an attempt to correct this.

The WCS parameters are set close enough so that it is easy to identify star 
fields.  I will make another correction to this tonight in an attempt to 
get it closer.  Is presently in error west by 4' of RA.

The result of all this is the roundest stars that I have yet seen.  The 
only real problem in the data last night was frost on the V window.  It is 
dryer tonight so I hope that this will go away.  It was slowly clearing 
through the night.  There oil bubbler seems to be working, there is no 
evidence of ice on the CCD's though the V camera has marks on it caused by 
old ice crystals.  I think there will be no way to clean this 
off.  Hopefully these marks can be reduced by the flat field.

Except for the frost on the V window, the data last night should be good 
enough to star looking for short period variable stars and 
planets.   ;^)   Well, at least short period variables.  With detection set 
at about 5 sigma, there were 8000 stars in the I image and 5000 in the 
V.  With 60 exposures of the same field in each filter, one should be able 
to combine images and get better S/N.  It would appear that we can get to 
about mag 15 stacking four 100 second exposures.  Since we are so close to 
a full moon, the S/N should be better on a dark evening.

Tom Droege