Mag compensation and the database

["Gutzwiller, Michael" <mgutzwiller@lanvision.com>]

Hello all,

Hi all,

I've been working on a new version of the star program and a flat
compensation program and was wondering how to accommodate the changes in
the database.

The changes to star have been scattered in several areas and are about
ready to go.  The only change to the output would be to add another
column to the star list which is the magnitude adjustment for each star.
While the star program would put the same value in the column for each
star, the flat compensation program would modify this value when a star
list has been adjusted.

The real question is how to put these values in the database.

A little background is necessary.  After star matches the stars in the
list to the catalog it adjusts all the magnitudes by the median
difference between the catalog stars and the raw data.  The adjustment
is put in the header as the "Mag adjustment" value.  Thus the magnitude
listed is:

mag in list = raw magnitude + mag adjustment

This essentially corrects for the transparency, etc. in each image.  I
believe Chris's scripts use this adjusted magnitude, not the actual raw
magnitude, when storing lists into the database.  So far so good.

The flat compensation program that I have been writing, and that Glenn
has been generously testing for me, tries to determine if there is a
bias in magnitude as a function of the X coordinate along the image row.
To do this it compares the differences in magnitude between the Tycho
magnitudes and the adjusted magnitude.  Once a compensation array is
determined the program can then adjust the magnitude of all the stars in
a list based on their X coordinates.

Currently the program puts the newly calculated magnitude and the new
adjustment into a new star list where each star then has its own
adjustment.  This modified list could then be read into the database but
we don't currently have a way of storing an adjustment for each star. Is
this the way to go?  Or should I readjust the program to work against
the database and create a compensation table or should the observations
tables add a new field containing the adjustment?

Opinions?

Mike Gutzwiller