Astroalign: A Python module for astronomical image registration
This provides a practical tool for astronomers to align images for stacking or difference image analysis, though it is incremental as it builds on existing triangle-matching techniques.
The authors tackled the problem of astronomical image registration without relying on WCS information by developing a Python module that matches 3-point asterisms to find linear transformations, enabling alignment of images with varying point-spread functions, seeing, and atmospheric conditions.
We present an algorithm implemented in the astroalign Python module for image registration in astronomy. Our module does not rely on WCS information and instead matches 3-point asterisms (triangles) on the images to find the most accurate linear transformation between the two. It is especially useful in the context of aligning images prior to stacking or performing difference image analysis. Astroalign can match images of different point-spread functions, seeing, and atmospheric conditions.