MaxIm DL includes a mosaic generation capability as part of Autosave Sequences. Using this feature, it is possible to build up image mosaics covering a large area of the sky. It ensures that the individual tiles are evenly spaced across the area of interest, which greatly simplifies assembling the mosaic afterwards.
The mosaic should be captured with a certain amount of overlap between tiles. This provides an area for ”feathering,” which gradually blends the output from one image to the next. This prevents hard edges and other artifacts.
Starting out with a large blank document, use the Mosaic command to add the individual tiles. For images containing stars, you can automatically align tiles as you place them; simply place a tile approximately in position, then click Snap to pop it into place automatically. If you turn on Auto Background Equalization, the overlap areas on the edges of the tiles will be compared and an adjustment automatically made to match them up in brightness.
Try to make sure that the source images have the same exposure and that the sky conditions are the same. If the background levels change, it can cause problems with the blending. Flat-fielding is particularly important; any vignetting will show up as a pattern in the final mosaic. If necessary, use the Flatten Background command on each image prior to building the mosaic.
You should also make sure that there are no edge artifacts from your camera. If there are, they should be cropped off before trying to assemble the mosaic.