Tuesday, July 20, 2021

Galaxy of Andromeda

The Persian astronomer Abd ar-Rahman as-Sufi (Al Sufi) was the first to describe the Andromeda galaxy in 964 according to hand-written parchment.

Abd al-Rahman al-Sufi’s Book of the Fixed Stars, dating from around AD 964, is one of the most important medieval Arabic treatises on astronomy. This major work contains detailed star charts and an extensive star catalogue, which lists star co-ordinates and magnitude estimates.

1,000 years ago in his book he wrote: “The two lines (of stars) begin from the nebula which is close to the 14th star [in the constellation of Andromeda] …”. Here he is describing the constellation of Andromeda, and for the first time in recorded history he mentions the location of a nebula which is now identified as M31, the spiral galaxy in Andromeda.

Simon Marius was the first observer with telescope of the Andromeda Nebula in December 1612, and gave the first description of this object based on telescopic observation. He described it as resembling the light of a candle flame seen through translucent horn.

In 1781 Charles Messier of France listed it as No. 31 in his catalogue of nebulous objects, and to this day the Andromeda nebula is also commonly known as Messier 31, or M3l.

Modern observations of M31 date from 1914, when V. M. Slipher, using the 24-inch refracting telescope at the Lowell Observatory in Flagstaff, Ariz., determined that the solar system and the center of M31 are approaching each other at a speed of 300 kilometers per second.

In 2012 researchers concluded that Milky Way and Andromeda are going to collide in around four billion years. Andromeda is approaching Milky way at about 110 km/s.
Galaxy of Andromeda

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