Strange Cross Hatch Pattern

[kerrywaz1]

Hello All,

I have an Ha image that is a combination of 70 Ha frames dark subtracted and calibrated using a superbias generated from 55 bias frames. The image has a strange cross hatched weave pattern that appears in the lower signal areas of the image. Attached is the image stretched with the STF Autostretch boosted  tool.

Anyone know what is causing this or if I am ding something wrong with the bias subtraction?

Thanks,
Kerry

[pfile]

i sometimes see this kind of thing in narrowband exposures when i don't use flats - in fact the crosshatch pattern is visible in my flats... is this a camera with a kodak sensor?

rob

[kerrywaz1]

Yup - a KAF-16803 sensor.

I used flats. The round artifacts in the image are lens flares from the moon or bright stars.

--- Kerry
 

[pfile]

oh - have never seen a flare like that before, thought it was no flats...

maybe it is worth trying with a regular master bias instead of a superbias.

rob

[GregW]

debayer correctly?