Re: solution for matching problems

[Tom Droege <tdroege2@earthlink.net>]

Michael and all,

Hmmm!  In my copy of astrom.param the value of astrom.mag was 2 not 3.  I 
changed it to 4 and the program produced a full set of .clt files but then 
did not make the .cal files.

Slowly I am learning what you are doing, but there is a lot of stuff to dig 
through.

Tom

At 06:20 PM 4/14/02 -0400, you wrote:

>   I finally found time to look at the problem.  Thanks to Tom for
>providing some disks with sample data sets which exhibit the problem.
>The matching problems are caused by two factors:
>
>        1. the existing reference catalog doesn't contain a great
>               many stars in the proper magnitude range.
>
>        2. the pipeline was picking the brightest N stars from the
>               reference catalog in the B-band, and using those
>               to match against the detected stars in V-band and I-band.
>               Whoops.  This one was really my fault.
>
>   By making a small change to the code in "astrom.tcl" and the
>"astrom.param" file, I addressed number 2.  By making a somewhat
>larger version of the astrometric reference catalog, I addressed number 1.
>After making both changes, I was able to match all V-band and I-band
>images in Tom's disk set for 020205, starting with Hxra2310540.fits.
>
>   I'll distribute the fixes in the near future.  In the meantime,
>one very quick and easy change which alleviates the problem is
>to change
>
>                astrom_mag
>
>in the file "astrom.param" from "3" to "4".  That indicates that the
>V-band magnitudes from the reference catalog should be used to pick
>the brightest N in the area of the TASS image (rather than B-band).
>It may permit an extra 50% of the I-band images to pass the matching step.
>
>                                          Michael Richmond
>
>