Align by WCS
The Align by WCS command uses the world coordinate information stored in the image headers to align images to sub pixel precision. This command works with an image set. Alternatively, if no WCS calibration exists, or for general purposes, you can also align images using the Register Images command.
Note: This command may not give accurate subpixel alignment for images where the alignment involves higher order coefficients that are saved to the headers using non-standard keywords.
Run this command from the Image Window > Coordinates menu.
Load the target images as an image set in a single Image Window.
Bring to the top of the stack the image to which the others will be registered.
Use the Align by WCS command to align all the images to the reference image. The alignment can be removed by using the Undo command.
You can also view all of the WCS related keyword data by using the WCS Keywords command.
Register Images, World Coordinate System, Image Sets, WCS Keywords