Incompatible image geometry

[bfleming]

I’m new to Pi and still having problems with incompatible image geometry whe trying to do my flats
Using a EOS DSLR and rasa 11 inch
Darks and bias done off telescope and using skyflats (AV mode)
Happily makes super bias. And master darks but every way I try to make a master flat I get the the above error
Would appreciate some help
Regards Bryan

[RickS]

Hi Bryan,

Without more details it's hard to hazard a guess as to what is going wrong but there are three things which determine the geometry of a sub - the width (pixels), height (pixels) and depth (number of channels.) I'd be checking to make sure that the bias, darks and flats are all compatible.

Cheers,
Rick.

[bfleming]

thanks
ill try again
regards Bryan

[Steve G D]

Binning can cause this issue, if at least one of the flats is binned differently than the others, or if the stack is binned differently than the frame you are trying to calibrate.
If any of the images are cropped differently you will also get the incompatible geometry error.

Also, since you are doing sky flats, there is a chance PI is detecting stars that you can't see. If it does, and the flats are not registered to each other, it will recognize this and refuse to stack the images because they are not registered (which is reported as incompatible geometry. Try star alignment on your flats if the first two are not the problem.