Re: DS24 problems

[Andrew Bennett <andrew.bennett@ns.sympatico.ca>]

On Fri, 17 Jan 2003 15:24:52 -0600, Tom wrote:

>This is a problem caused by a deteriorating RA drive.  I have since fixed 
>it.   I believe I mentioned this in a post here.  OK, I just looked, and I 
>mentioned "cork screw" shaped stars in the 12 Jan 2003 23:16:05 
>post.

I can't find any corkscrews. Probably using a different
viewer! My PSF fitting said that the images were consistent
and not erratic. The stars are a bit comatic and a bit fuzzier than
one might like. The 6 selected images on the other hand show
clearly double images. The separation has the same position
angle (as measured by my eyeball) but different magnitudes
for the three pairs.

The separation is definitely not E-W. I don't see how it
happened if it was only the RA drive having problems.

Another problem, for me, is how my code coped with 5 out of
6 without setting any flags! The one I checked in detail
appears to have processed two complete sets of stars and
then to have chosen one of the sets for the astrometric fit
without once getting confused ... or even noticing that it
might get confused. While there is much to be said for
robust code - it is, of course based on Michael Richmond's
Match routines - this is going a bit far! Over 800 stars
were used for the fit: over 800 close pairs were rejected
correctly.

Andrew Bennett, Avondale Vineyard