#libremonday
Hugin [http://hugin.sourceforge.net/] is a panorama stitching software but that is not all that it is useful for.
I use Hugin for aligning image stacks, in astrophotography or super-resolution images. Its quite good out of the box in stitching and aligning, but it also allows you to set control points and modify settings easily enough if the default settings do not work.