NASA releases Andromeda Galaxy comparison showing digital processing techniques

NASA has released a comparison of the Andromeda Galaxy (M31) showing the image before and after digital processing to demonstrate the techniques used in astrophotography. The original data consists of 223 individual 300-second exposures captured by photographer Kees Scherer from an observatory in Portugal in 2019.

The purpose of the digital processing is to remove environmental and technological distortions rather than to alter the actual appearance of the galaxy. The raw images contain various artifacts caused by human activity and atmospheric phenomena, including parallel airplane trails, continuous satellite streaks, short cosmic ray traces, and defective sensor pixels.

To clean the images, professional astronomical software such as Astro Pixel Processor, DeepSkyStacker, and PixInsight was used. These tools employ mathematical algorithms to identify and automatically discard moving or unwanted elements, allowing for a clearer recreation of the galaxy's structure by minimizing terrestrial interference.