[Aavso-photometry] How can I beat the FLIP?

[Michael Koppelman]

As others have said, the flat is probably the most likely culprit. I 
don't think trying to get everything back on the same pixels is the 
answer since it is nearly impossible and it just kind of hides 
uncertainties anyway. Have you tried using larger apertures? You want 
to average out the differences in the pixels and the flat and such.

Just a few thoughts.

Cheers,
Michael Koppelman
http://www.lolife.com/astronomy/



On Dec 28, 2004, at 5:46 PM, Brad Walter wrote:

> However, when I look at the magnitudes before an after the
> meridian flip, the means of the measurements of the two runs are more
> than a three sigma confidence interval apart. The only thing I can
> attribute this to is change in location of the stars on the CCD.