M31, also called the Andromeda Galaxy, is the largest spiral galaxy close to us. Its distance, 2.5 Million light years, together with its intrinsically large size, allow this object to be seen with the naked eye. It is considered to be the farthest object to be seen with the naked eye, although there exist some claims of people that can see some farther galaxies. Its two largest satellites, M32 and M110 are bright enough to have made their place in the Messier Catalogue. M31 has been “discovered” many times in recorded history. The earliest known record belong to the Persian al-Sufi, 3,000 years ago. M31 contains about 10^12 stars (10 trillion), three times as many as the Milky Way. M31 belongs to our local Group and is heading towards us. It will “collide” with the Milky Way twice, the first one in about 1.5 billion tears from now and the second one about 2.5 billion years later. What a beautiful sight for our fellow astronomers by then!!
This image has been displayed in Hugo Giovannetti’s Facebook page (Space Learner) on 25 September 2018.
Name(s): M 31. NGC 224. Andromeda Galaxy
Type: Spiral Galaxy
RA: 00h 42m 43.7s
Dec: +41º 16’ 01”
Size (arcmin): 190×62
Distance: 2,500,000 ly
Location: iTelescope.net, Mayhill, NM, USA
Size (arcmin): 230×135
Telescope: Takahashi FSQ 106; f/5
Camera: SBIG STL11000M (40086x2672pix)
Total exposure: 90 min (L: 3x10min; RGB: 4x5min)
Processing: CCDStack, Photoshop CC 2016 and PixInsight