Weird scale transformation in X direction when aligning during stack
Stacking program, astrometric (plate) solver, fits file viewer
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han59
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Hello Han,
I was having difficulty stacking a series of subs for M 78 yesterday. The final stack image ended up with triple stars down the right hand side, the spread for an individual star increased the further right it was in the frame. Eventually, by using a combination of the stack method "Align and Calibrate" and then using the Blink tab with align images switched off I was able to indentify the handful of frames that were causing the issue.
Using photoshop layering I have narrowed the issue down by comparing the unaligned and aligned versions of the same file. ASTAP appears to be scaling the aligned image a small amount in the X-direction.
The attached file is a screen grab from Photoshop showing the original and aligned images over layered with the layer handling set to "Difference".
I do not currently have a good internet connection for uploading large files but if you need more information I can upload more info when I get home after 20th Jan. For now I know how to indentify offending files if it happens again. There were about 6 files out of a 150 in which this happened.
Kind regards,
Phil
No problem. Share the images and I will have a look.
This could be caused by a bad reference image. Inspect the image which has a small crown behind.
Han