[PRejto (Peter)]

Hello,

I'm seeing an odd looking problem on all of my flats using some older grear that has not been used for some time. The illumination is from a Gemini Snap-Cap at 5% brightness. The flat illustrated was 3 seconds 1x1 from a Moravian G2-8300 through astronomic Deep Sky filters and an ONAG XT.

The sample is from 30 frames created in CCDStack, bias subtracted. The individual flats also indicate a faint striation that has become enhanced through the master flat creation. All the flats, including ha, show this pattern but blue the least (with a longer exposure).

I suspect the Snap-Cap might be responsible but never noticed this in the past. I will take some flats using a different light source. In the meantime, has anyone seen something like this before?

Thanks,
Peter