PhotometricMosaic: The Mosaic Stitching Script

If you want to shoot a large sky region and stitch several frames into one big image (a mosaic), PixInsight’s native mosaic process sometimes falls short. PixInsight’s script library ships with PhotometricMosaic, developed by John Murphy, which solves some of the problems the native process can’t handle, and it’s a tool well worth knowing if you play with mosaics.

What PhotometricMosaic Is

PhotometricMosaic is a mosaic stitching tool built into PixInsight’s scripts, authored by John Murphy. Compared to PI’s native mosaic process, it handles some joining problems the native process can’t solve (for example, the photometric differences and gradient seams between adjacent frames).

Watch out for the version issue: PI’s built-in version was stuck at 3.4.3 for a while, whereas the author’s website actually has an updated 4.0 version, complete with full 4.0 documentation.

Installation: Switching to Repository Auto-Update

There’s a bit of version evolution to note here. Early on, to update to 4.0 you needed to manually download and install from the author’s website. Later, PixInsight removed the built-in PhotometricMosaic, and the author John Murphy also changed the script to an auto-update installation method.

The current method is: add the following URL to PixInsight’s Repository, and it will install and update automatically:

https://pixinsight.astroprocessing.com/

Once the Repository is added, PixInsight will automatically fetch the latest version, and you won’t need to manually download files anymore.