The new Astroart 9 demo:
one new feature:
"Automatic mosaic from plate solved images."
And it will correct for optical distortion.
load two or more overlapping images that have been plate solved, or load them and plate solve them:
Dropdown menu->Tools->plate solve
then with both images open: drop down menu->Image->mosaic and select one of the images from the menu presented; click on OK and it will create the mosaic:
M81 with a 10in F7 SCT and M82 with a 10in F5 SCT (both with Orion SSPro APSC cameras) mosaic image from two images taken years apart. Processing via Astroart 9 Demo.