Declination Drive

[Tom Droege <tdroege2@earthlink.net>]

The new declination drive is working just fine.  Every so often the wind 
blows hard and the drive wiggles a little, but then we do not usually get 
clear sky with high wind around here.  TOM2 and TOM3 are better protected 
in the dome so this will be less of a problem there.

I now have a little data taking images on a 4 degree grid.  A measure of 
how well the drive works is to take a grid, reduce the stars and then look 
at the stars with two observations.  There should only be two observations 
in the overlap regions.  Plotting the result I get a nice grid.  Just lines 
of stars in the overlap regions.  They seem quite regular.  At least good 
enough.

I am patiently trying to accumulate enough data so that I can see the 
statistics of the measurements where each star is always measured on the 
same spot on the ccd.

The 7x7 data will go into the mail today.  I am hoping that one of you will 
either determine what we are doing wrong, or generate a correction based on 
the 7x7 data.  The data looks very regular so that I am optimistic that a 
correction will work.

Tom Droege

At 11:36 AM 11/20/02 -0600, you wrote:
>I need some good sky to tell for sure, but the new declination drive looks 
>like it is working very well.  It is also much stiffer than the old 
>scheme.  Roughly as stiff as the old scheme with the clamp on.
>
>Indications are that it repeats to a few minutes of arc.  I won't really 
>know until I get a couple of nights of clear sky.  This might not be until 
>February.  ;^)
>
>I am slowly getting all the telescopes lined up and calibrated.
>
>I got some furniture glides at the hardware store  and stuck them on the 
>bottom of TOM1.  With a bolt in one corner and a steel ruler nailed down 
>at another I can now rotate TOM1 to 0.1 degree or so.  This should fix the 
>diagonal stars.
>
>I am running a program that produces a 6 x 6 array of images.  This should 
>produce some stars that appear in 36 different positions on an 
>image.  When I get some data taken this way, I will send it out to all of 
>you that are eager to work on the calibration.
>
>Those of you with Mark IV systems that want to upgrade, write me 
>privately.  I will make up a kit and send it out.  The big problem is 
>going to be to figure out how to tell you to do it.  I think I will just 
>take a couple of pictures and then let you all ask questions.  I think 
>that this is really the "last" thing that prevents a good survey from 
>being taken.
>
>Tom Droege
>