Re: GSC 748-1618

[Stupendous Man <richmond@a188-l009.rit.edu>]

  Suggestion: Michael K's measurements are, I believe, differential
with respect to a comparison star.  The TASS values are based on
ensemble photometry, using many stars over a frame ... and since
the field centers aren't always the same, the stars in the ensemble
can change.  In addition, the variable and the comparison star
are wandering around through the field from night to night in the
TASS dataset.

  One might make a fair comparison between the datasets in this way:

       a) make a light curve using Michael K's differential measurements
       b) select the TASS values for the variable (has already been done)
       c) select the TASS values for the comparison star
       d) calculate a differential value from the TASS data:

                  TASS variable - TASS comparison

       e) compare the two sets of differential measurements

  I'll bet a dozen donuts that the scatter in the TASS measurements
decreases significantly.  

  Of course, this only makes sense if the comparison star appears
in a significant fraction of the TASS images.

                                       Michael Richmond