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Working with FITS files

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#1 tjay

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Posted 24 August 2021 - 05:57 PM

What's the typical workflow that people use for dealing with FITS files?

 

I've got an older version of Photoshop, an older version of Corel Paintshop Pro, and the latest version of GIMP, and none of them seem to deal with FITS files from Sharpcap very well.  GIMP seems to load everything an monochrome, and Paintshop Pro and the version of Photoshop I've got don't handle FITS files at all.

 

I've tried FITS Liberator, but I don't seem to get how to use it, as again, it seems to treat FITS files a mono only.

 

Thanks in advance!



#2 Professor2112

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Posted 24 August 2021 - 06:19 PM

I usually use APP for stacking and processing, then save as a 16bit tiff.  After that it’s photoshop for noise reduction and some tweaks if needed.  To just sift through my individual subs to weed out any bad ones, I use the FITS viewer in zwos free software “asi studio”.  I’m sure others can help you figure it out on your existing software though.  Unfortunately I can’t help you there, I’ve only ever processed the actual FITS in APP. 



#3 Tapio

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Posted 24 August 2021 - 06:49 PM

You stack the fits files with whatever stacking software you are using and then output the result as tiff file.

#4 xiando

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Posted 24 August 2021 - 06:49 PM

If all I have is a FITS final image, (my final in DSS is a FITS file but I often just use the screen image dumped to a TIF), I push them through Fitswork and generate a tif output.

 

I never open FITS files from photoshop.



#5 bobzeq25

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Posted 24 August 2021 - 06:58 PM

fits is an astro specific format.  It's what astro specific processing programs use.

 

Which are significantly better than the alternative of trying to persuade a terrestrial editing program to do astro.

 

That said, Fits Liberator works.  You have to debayer the files to get color.  There are a number of ways to do it, but I have no experience.  You should be able to find them online.

 

This may be helpful.

 

https://stargazerslo...o-rgb-channels/


Edited by bobzeq25, 24 August 2021 - 07:00 PM.


#6 OldManSky

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Posted 24 August 2021 - 07:25 PM

In DSS you can select the format of the final stacked image, FITS or TIFF. Select TIFF and you can open the files directly in PhotoShop or other imaging programs.


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#7 tjay

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Posted 24 August 2021 - 09:31 PM

Thank you for all the quick responses! I'll give them a try!

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#8 acrh2

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Posted 24 August 2021 - 09:38 PM

Gimp reads fits files.



#9 Alex McConahay

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Posted 24 August 2021 - 10:31 PM

>>>>>GIMP seems to load everything an monochrome, and Paintshop Pro and the version of Photoshop I've got don't handle FITS files at all. I've tried FITS Liberator, but I don't seem to get how to use it, as again, it seems to treat FITS files a mono only.

 

All astro image files are mono files. If you are using a One Shot Color camera, there is a special filter array (A Bayer array) in front of the pixels so that one out of every four collects red, one of four collects blue, and two collect green. But the sensor behind those filters are all monochrome. They sense only intensity, not the color. 

 

It is only when you DeBayer the image that you get a color image. DeBayering is a mathematical formula that interprets the color values of the various pixels by comparing them to the neighboring pixels. 

 

So, when you open a FITS file in any software (that does not DeBayer) you will see a monochrome image. Just gray.

 

Alex


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#10 tjay

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Posted 25 August 2021 - 10:16 PM

So using Deep Sky Stacker seems to be the most straightforward way for me right now.

Now I just need more images to play around with.

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#11 tjay

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Posted 25 August 2021 - 10:18 PM

>>>>>GIMP seems to load everything an monochrome, and Paintshop Pro and the version of Photoshop I've got don't handle FITS files at all. I've tried FITS Liberator, but I don't seem to get how to use it, as again, it seems to treat FITS files a mono only.

All astro image files are mono files. If you are using a One Shot Color camera, there is a special filter array (A Bayer array) in front of the pixels so that one out of every four collects red, one of four collects blue, and two collect green. But the sensor behind those filters are all monochrome. They sense only intensity, not the color.

It is only when you DeBayer the image that you get a color image. DeBayering is a mathematical formula that interprets the color values of the various pixels by comparing them to the neighboring pixels.

So, when you open a FITS file in any software (that does not DeBayer) you will see a monochrome image. Just gray.

Alex

I thought that debayering was done by the software like Sharpcap before writing to FITS format.

I see that I can save each channel separately in FITS Liberator but how do I recombine them into a color image?

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#12 Alex McConahay

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Posted 25 August 2021 - 10:25 PM

I thought that debayering was done by the software like Sharpcap before writing to FITS format.

I see that I can save each channel separately in FITS Liberator but how do I recombine them into a color image?

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You may be right.....I do not know how SharpCap in particular does it. 

 

My OSC camera, captured in SGP or in the ZWO software, saves the file whole, without DeBayering. And they work as I described earlier. 

 

I shall sit back and see whether somebody with SharpCap experience can answer. 

 

Might I suggest you simply try to Debayer whatever file you have and see if it comes out an appropriate color image....

 

Alex


Edited by Alex McConahay, 25 August 2021 - 10:25 PM.


#13 Gamewarden

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Posted 26 August 2021 - 08:01 AM

SharpCap only displays at the time in colour. If moving files to another program they have to be debayered first. I use the program PIPP to get the colour back.



#14 tjay

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Posted 26 August 2021 - 09:27 AM

SharpCap only displays at the time in colour. If moving files to another program they have to be debayered first. I use the program PIPP to get the colour back.

Thanks, I will give that a try.

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