M31 mosaic in a Canon 60Da

This is a work in progress during the fall. My plan is to take sufficient frames to build a three by three mosaic of M31.I've added a few extra frames that I could not get to match manually. After downloading Microsoft's Image Composition Editor (one of the simplest and best mosaic tools I've worked with) I managed to get the two bottom frames to blend properly. Scroll down to see higher resolution frames of the mosaic. The mosaic is stored at a high resolution so zoom in and scroll around.
Object M27, RA 00:42.7 Dec  41:16
Exposure 30 minutes (10 X 3 minutes) for each frame of the mosaic
ISO 1600
Camera Canon 60Da DSLR
Optics 200mm SkyWatcher f/5 Newtonian reflector with Paracorr for a total  focal length of 1150 mm
Location St.Croix Observatory, St. Croix, N.S.
Processing Calibration and stacking  Images Plus . Images aligned in Registar and an arcsinh stretch was applied in Images Plus to brighten the image enough so that the spiral arms were visible. The mosaic was built in Images Plus using layers and curves to match brightness at the edges and blurred masks to blend things together. Stars split from the image and multi-scale decomposition used on the galaxy image to increase the contrast and detail. The detail  layer from the decomposition was blended with the original using the merge split blend mode. Multipoint flatten was used to flatten the image and remove a small gradient. Since the image is a little low on exposure, two passes of masked noise reduction were applied concentrating on different frequency bands in each pass. Finally the stars were recombined with the galaxy and the resulting image binned by two.
Center left
Center right