FIT Headers to Add for CMOS

Sorry if i bother you all … ASI native driver is finished … now i’m testing all.
I’ve added the FIT headers you found in image (red box) about GAIN, OFFSET and USB LIMIT.

Due to the fact that i dont have experience on CMOS , are the header names correct (for who use this cameras) ?
I refer to processing applications that use this parameters or other application could use.

Thanks for help me.

Hi Leo,

AstroPixelProcessor uses the FITS header keyword “Gain” to match calibration frames with lights, so yes, Gain is the right choice for that.

As far as I can tell, PixInsight just assumes you are using matching calibration frames (same gain, offset and USB Limit), so having the FITS header keywords is very useful for the user, but requires some discipline on the user’s part. AstroPixelProcessor does give you a warning if the Gain values don’t match.

Maxim DL creates files with a keyword of “EGAIN” which APP does not recognize, so it will be very helpful to have the GAIN keyword in our FITS files.

I’m sure others can help with info on other processing tools but those are the two I’m primarily using.


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GAIN, OFFSET and USB LIMIT is exactly what I would like to have in the FIT header. I mainly use PixInsight, which I believe will not take advantage of them, but I would find them extremely useful for my own file management and manual processing purposes.

Kind regards,


So this mean is correct how is now … thank you

Leo, this is wonderful.

I agree with Glenn as to filing by header information. This makes categorizing after the fact much easier.

Thank you.


Hi Leo,

I also agree. I’ve been waiting for this more than anything else. This is wonderful news and thank you very much for all your effort; it will make processing and also allow longer term categorisation much easier.

Best wishes