Registar and FITS files

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solo05
Posts: 27
Joined: Thu Apr 11, 2013 9:39 am

Registar and FITS files

Post by solo05 »

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 :shock:

"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
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admin
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Re: Registar and FITS files

Post by admin »

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
Ivo Jager
StarTools creator and astronomy enthusiast
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