Author Topic: Another Flats problem  (Read 788 times)

Offline tdgm

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Another Flats problem
« on: 2017 May 27 11:38:11 »
Hope this is not something already discussed but I am having a problem removing the dust donuts from my image (recently). I created the flats like always and then pre-processed like always but tyhe dust donuts continue to be present. They are actually reversed in the integrated image. Below is a screen shot of a single flat field image on right and a integrated image on the left What am I doing wrong. This is a recent problem in the past everything has been fine.



Steve


Offline tdgm

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Re: Another Flats problem
« Reply #1 on: 2017 May 27 11:40:07 »
I apologize if the image of the flat field is not to good hopefully someone can help me with this problem



Steve Herrman

Offline Greg Schwimer

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Re: Another Flats problem
« Reply #2 on: 2017 June 03 22:08:57 »
I've seen this happen if you calibrate a flat twice with for bias. For example, if you calibrate the flat with a bias master as well as a dark master that has also been calibrated with the same bias.
- Greg
Scottsdale, Arizona, USA