Align on Point

The Align on Point command accurately registers an Image Set by shifting the images relative to a point source, such as a star. Images aligned by this method should have no significant field rotation or difference in image scale. If these requirements are not satisfied by the Image Set, or you need to align on an extended object, see the other alignment tools listed below.

Execute this command from the Process > Alignment menu or from the Animation Bar by right-clicking the button and then using the menu command.

This command is also operated using the 'A' keystroke command when the Image Cursor is placed near the peak of a point source.

This command has no control dialog and it is available only when an Image Set is opened in the top-most window.

How it Works

This command aligns on a precise coordinate by computing the centroid position near where you click on the first image. It then tracks the centroid position through the image stack in order to determine the offsets needed to bring the images into alignment. This uses the "global" centroid command, which is the same one used in the Measure menu and the Image Bar. Therefore, the centroid settings are taken from the current parameter profile in the Default Centroid Properties dialog.

Procedure:

Make the target image window the top-most window.
Execute this command from the Process menu.
Click the mouse on the reference point that is to be aligned in all images.

If you do not like the result, use the Undo command to remove the alignment.

Other Alignment Techniques

There are two other image alignment methods available:

Align on Object: Use this command when the alignment object is extended, such as a planet, galaxy, or nebula.

Image Registration : Use this command when one or more of the images differ in scale or rotation, or have other deformations like non-square pixels or non-perpendicular axes.

How it Works

Procedure:

Other Alignment Techniques

Related Topics