RA/Dec of stars change after color seperation

Posted by ghawkins on Jul 10, 2023; 10:16pm
URL: http://astroimagej.170.s1.nabble.com/RA-Dec-of-stars-change-after-color-seperation-tp2262.html

Hi Karen,

After months of terrible observing weather, the skies have finally cleared a little.

Last night I did a tri-color run on Bp Peg.  I tried using the debayer option to achieve color separation in G, B, and R of plate-solved images (done with ASTAP).  I noticed the RA/Dec of stars in the 1/4 images were slightly different and incorrect compared to those in the original image. For example, BP Peg was reported at 21 33 13, +22 44 25 in the original image (correct), and 21 33 45 +22 34 35 in the 1/4 image (wrong). I tried the same color separation function with ASTAP and the coordinates carried over correctly.  

Best regards,

Gary

PS: Would it also be possible to append TG, TB, or TR to the filenames of the respective 1/4 images? It just makes it obvious what color you are looking at.