Mark IV Data Option(s)

[Glenn Gombert <gleng@infinet.com>]

Hello Mark IV Data Fans,

    There has been _lots_ of good discussion on the list recently
regarding the current Mark IV data and what could be done to improve the
quality of the image data. There seems to be three different proposed
courses of action "on the table"

    (1). The best (and most desirable) solution as has pointed out is to
correct the lens configuration to eliminate coma. This will be an on
going effort that will probably wait until the correct person(s) /
resources can be brought to look into the problem...

    (2). Determine correction factors to correct for coma effects in
Mark IV images. This mat be possible to do (but it will not be easy) as
Michael has previously mentioned. I think that Mike G. is going to look
into this and see  if his "FlatComp" program could be modified to
perform some sort of adequate correction for the current Mark IV
hardware configuration..


  (3). Crop the center half of each Mark IV image (as Michael has
mentioned in Tech. Note 59) to limit the effects of coma from degrading
the photometry measurements. I am going to modify the current Mark IV
processing program (as an option) to crop each image to the center 1/2
of each image to process the current batch of data that I recently got
from Tom. This seems to be the best "interim" approach given the current
options that have been looked at.....

Happy Y2K To All!!
Glenn G.