Astrophotographer Revives Challenging M31 Image After processing Hurdles
An astrophotographer has shared a detailed account of overcoming meaningful processing challenges to produce a striking image of the Andromeda Galaxy (M31), captured with a 135mm lens and a 2600MM camera. The project, initially plagued by difficulties in gradient extraction and color calibration, ultimately required a complex workflow involving separate RGB and Luminance layer processing, star removal, and final edits in Capture One.
The pursuit of a refined M31 image led the photographer down a path of experimentation with tools like GraXpert, RC-Astro, and Drizzle, revealing the intricacies of deep-sky image processing. Initial attempts with Drizzle proved problematic due to color calibration issues,necessitating a complete reprocessing of the data. The final result,while exhibiting high saturation and some noise,represents a long-term effort to realize a specific aesthetic vision – an “American image” – and salvage previously abandoned sessions.
The photographer initially struggled with gradient extraction, recalling numerous abandoned attempts. A key step involved rounding stars, which introduced them to specialized astrophotography plugins. sampling at 5.7″ per pixel prompted exploration of the Drizzle integration technique, ultimately abandoned due to color calibration complications and issues with luminance deconvolution.
The final processing pipeline involved stacking raw files in PixInsight, processing RGB and Luminance layers independently, utilizing Starnet for star removal, and employing erosion techniques to reduce star artifacts before reintegrating them. Curves were adjusted in pixinsight, with final touches applied in Capture One. Despite a very dark sky, the photographer found it necessary to further darken the FDC to eliminate starless artifacts.
The resulting image, while visually rich, presented challenges with noise, which persisted throughout the HDRMT and MLT processing stages in pixinsight.The photographer is now seeking advice on mitigating this noise and improving the overall image quality. The image was edited December 1, 2025.