Canon EOS/fit format


#1

Hello has anyone been able to successfully process subs taken with a Canon camera and saved in Fit format as opposed to canon RAW? I for whatever reason, am not able to calibrate my frames and I suspect it has something to do with the way the pixel values are stored in the file. I am using pixinsight to calibrate my files and its default is floating point fits with a range of 0,1. All my calibration files were done using CR2 files straight off of my Canon and they were saved as floating point 0,1 range data.
I have a set of lights now taken with SGP that I am trying to calibrate using the old calibration files.
I saved my lights in FIT format using SGP for capture from my Canon.
Does SGP save FIT files off of a Canon DSLR using the TBLR orientation with the 0,65535 range?
That might be my issue that I need to correct.

This issue does not happen with my two QSI cameras.

I hope this makes sense.
Thanks

Andy


#2

I would not recommend mixing formats for processing. The cr2 are 12 bit and the fits have been scaled to 16. So that’s part of the problem. Also the conversion from cr2 into fits can drop columns and rows as the overscan can be treated differently. Plus, as you mentioned, the row order could also be different.

I would also recommend using the same application to capture your lights, flat, and darks for these same reasons.

Hope that helps,
Jared


#3

That’s good to know, I should have thought about possible format issues. Do you think that there is a way to recover my 8 hours of data saved in Fit format?
I wonder if it makes sense to remove the Canon/fit option from SGP altogether to avoid these issues.
In the future I will always use the CR2 format, however do you think that recapturing calibration data anew using SGP may salvage my light frames?
How are Fit files saved from SGP anyway, are they saved as signed integer? I can force PI to load fits as signed integer.


#4

Probably not… as soon as we remove one someone will ask for it back.

I do. If you want to save your light frames, take calibration frames in the same format and you should be good to go.

All FITS files are saves as (standard) 16-bit unsigned FITS files. The reasoning behind this is that almost 100% of astro-cameras deliver data in this format… we are just propagating it to a file.


#5

Great I am half way there. I captured flats ant darks but I was using old bias and probably that’s what threw everything off.
I will report back after the calibration attend with new bias.
Thanks for clarifying on the format.

Thanks!


#6

Quick update. I re-calibrated my image with frames taken the same way and it worked like a charm!


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