Re: Extracting green channel from FITS

Posted by Bill Tschumy on Mar 06, 2022; 11:06pm
URL: http://astroimagej.170.s1.nabble.com/Extracting-green-channel-from-FITS-tp1750p1850.html

OK, I shot some test images using ASIAir Pro.  I used the Red Green Blue image posted by Han.

This is with the most recent db5.0.4 AIJ build.

Unfortunately, something is still not right.  If I extract the Green channel using ASTAP, it looks very close to what AIJ gives for the Blue channel.  The AIJ Green channel doesn't look like it the ASTAP TG image at all.

I suspect ASTAP is correct because the Green rectangle is brighter in the green extracted image (as you would expect).  With AIJ it is the blue rectangle that looks brighter in the green extraction.

ASTAP: RGB_Test_TG.fit
AIJ: RGB_Test.fit (GREEN).fits

Maybe ASIAir Pro is doing something wrong with the keywords in the image

I am using RGGB for the Bayer pattern (which is also what ASIAir places in the fits file for my Canon 700D).

Here are the files:

https://www.otherwise.com/RGB_2.zip