Re: Extracting green channel from FITS

Posted by han.k on Mar 03, 2022; 1:08pm
URL: http://astroimagej.170.s1.nabble.com/Extracting-green-channel-from-FITS-tp1750p1822.html

Hi Karen,

I was not aware AstroImageJ did something similar. I tested it using the latest AstroImageJ and studied the exported TIFF file.

Using a hex editor and TIFF analyse program, I can see the full FITS header is stored by AstroImageJ in tag 50389. That's very interesting. This is more or less the same solution as developed and implemented by some programs now. The only major difference is that we use the standard ImageDescribtion tag 270 and ASCII rather then byte format. The advantage of tag 270 is that it is always available in TIFF readers. Tag 50389 is not always readable by TIFF readers and could be overwritten.

Assuming this is an easy modification can your consider adding support reading tag 270 ?
AstroImageJ already writes a small amount of info in tag 270.

The so called Astro-TIFF sample using tag 270 are all available in the specification webpage:
https://astro-tiff.sourceforge.io/


Thanks, Han