StarTools

Hi Ivo

I asked some time ago about putting fits files through Registar as their website was a bit ambiguous as to how it treats them.

I emailed last night and got the following back this morning

"Steve,

RegiStar currently reads 32-bit FITS files but converts them internally to 16 bit. We have had requests from users for internal 32-bit support and may implement this support in some future release.

Auriga Imaging"

My question Ivo is are we going to loose a lot of information if we use Registar or do you think this will work OK ?

Regards
Steve

Hi Steve,

You may lose some information when stacking a lot of images using certain statistical rejection techniques, but chances are that you're fine.

Assuming you're stacking DSLR images, the data they produce is typically 12-bit or 14-bit in depth, with some of the least significant bits carrying a lot of noise.

Theoretically you'd run out of bits to encode the stack with in 2^(16-14) = 4 stacked images or 2^(16-12) = 16 stacked images when applying pure averaging.

Pure median stacking will retain the bit-depth of the individual frames (e.g. 12 or 14-bit), while most other stacking algorithms sit somewhere in the middle (for example, ones that reject a number of frames that are considered outliers and average the rest).

At the end of the day, you will probably not notice any problems.

Hope this helps!

Ivo