M31 in high definition - Great Andromeda Galaxy with its halos and globular clusters (Matteo Marchionni)

M31 in high definition - Great Andromeda Galaxy with its halos and globular clusters

Back to an old friend, the Andromeda Galaxy. Last autumn I had one night of wonderful weather, with my rural sky going to Bortle 2. That night I decided to go back on M31 - the Great Andromeda Galaxy - and take two brief panels. Acquired data were wonderful and thus I decided to combine them with an old acquisition set of the same galaxy taken the year before (https://astrob.in/qhe93r/0/).

I processed all three panels with my new processing skills, in particular exploiting Russel Croman's Pixinsight tools. Then, I stretched them independently trying to achieve similar results. Non-linear, stretched, panels have been reprojected and merged in a single mosaic. To achieve the highest possible SNR and obtain clear stars I followed a specific pipeline for merging: I merged both with an "average" and "overlay" methods, then I extracted stars (with StarNet2) from "overlay" mosaic and combined with the background from "average" mosaic. Final elaboration with Photoshop.

For the annotation of astronomical object I highlighted Messier objects (M31, M32 and M110 galaxies) with purple circles, NGC objects with salmon circles and PGC galaxies with cyan circles. I also added known globular clusters thanks to a custom catalogue from Bologna Catalogue of M31 globular clusters and candidates, with orange crosses.

I am really amazed of how much details and structures can be detected on another galaxy just with such a simple astrophotography setup! Part of the faint halo surrounding M31 and M110 is visible and there are some globular clusters up to magnitude 20.
Really happy of this my new version of this stunning object, I hope it is not "just another M31 image"!

Clear sky to everyone!

Final
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B

Title: Annotated version

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