[Aavso-photometry] FITS test results so far

[Chuck Pullen]

Yes, I understand Arne.  Thanks.  If it gets that bad, I'm probably not 
even going to observe.  A possible exception might be a GRB.

Thanks

Chuck

At 11:01 2/10/05 -0700, Arne Henden wrote:

>Michael Koppelman wrote:
>
> > It is certainly enlightening to see how these different software 
> packages handle this. Clearly in most cases if images are combined the 
> TIME-OBS keyword needs to be managed manually.
> >
> > I almost never combine images and then do photometry. I always do 
> photometry and then average the photometry if I find I need to beat the 
> errors down. This allows me to do a weighted average if the uncertainties 
> are not equal. It also takes out the extra math involved with registering 
> and rotating images if there is some slight change in the field over 
> time. It's hard for me to think of a reason why one would stack images 
> before doing photometry. Can anyone help me?
> >
>You will find that most photometry packages start having systematic
>errors when working close to sky/low signal/noise objects.  It often
>helps to stack first to increase the S/N, then do the photometry.
>Arne
>
>_______________________________________________
>Aavso-photometry mailing list
>Aavso-photometry at mira.aavso.org
>http://www.aavso.org/mailman/listinfo/aavso-photometry
>
>