What rejection algorithm for dithered sky flats?

[Bmegdal]

I understand the recommendation to use aggressive percentile clipping for sky flats, but wonder if this still applies if dithering is used, or could better algorithms be used in the dithered case?

- Barry

[vicent_peris]

Hi Barry,

Skyflats should be always dithered to have all the stars in separate positions. If you don't make dithering, you'll have severe artifacts in you master flat frames. Therefore, the recommendation for percentile clipping applies to dithered sky flats.

Best regards,
Vicent.

[Bmegdal]

OK, thanks.  Makes sense now that I think more about it.

[mads0100]

Does turning off tracking count as dithering?

[Geoff]

Does turning off tracking count as dithering?

Any procedure that slightly changes the position of the image on the sensor is equivalent to dithering.
Geoff

[mads0100]

Thanks Geoff!