The Andromeda Galaxy

[VilleM]

This object is one of the few that need no introduction, it is the brightest galaxy visible from northern hemisphere. Visible even to the naked eye on a moonless night! The Messier 31 has been on my imaging list forever but I haven't done it any justice until now. In this two panel mosaic you can also see two satelite galaxies Messier 32 and Messier 110.
M31 was first described by Persian astronomer Abd al-Rahman al-Sufi in the year 964 as "nebulous smear" or "small cloud". Little did he know that this small cloud was home for estimated one trillion stars flying towards him 110 kilometres per second. M31 is one of about 100 observable blueshifted galaxies, it is expected to collide directly with the Milky Way in about 4 billion years creating a giant elliptical or a disc galaxy. Abd al-Rahman al-Sufi was certainly not the only one that studied this spectacular galaxy. Over time it was cataloged by Giovanni Batista Hodierna in 1654, by Ismaël Bullialdus 1664, Edmund Halley in 1716, and again by Charles Messier in 1764 in his famous Catalogue of Nebulae and Star Clusters giving it the designation we know today.

Taken with SkyWatcher Esprit 100mm f/5.5, ZWO ASI1600MM-C, Losmandy G11, guided with ASI224MC as finder-guider, TS Optics LRGB filters. L: 163x120s, R: 114x120s, G: 108x120s, B: 124x120s. Total exposure time for this two panel mosaic is 17 hours.

[peter shah]

beautiful!

[UKDiver]

Very nice.

Re the collision, I've read recently that the outer gas envelopes of M31 and the Milky Way may already be colliding.