Re: Analyzing Data

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

  Doug wrote:

> I suspect that a very successful minor modification to the
> WS statistic would be for it to calculate residuals from a
> given night's mean magnitude instead of a global mean magnitude.
> This would get rid of the effects of zero-point changes which
> aren't currently calibrated out.

  Doug, can you clarify that last statement?  The current pipeline
gives each image a zero-point value based on the instrumental magnitudes
of Tycho stars in the frame.  If two frames cover the same patch
of sky on two nights, they should share the same Tycho stars.
I don't see how large zero-point offsets could remain; perhaps I'm
looking at it the wrong way.

                                    Michael