Andromède au Quotidien Etoiles & Galaxies Constellation d' Andromède


constellation [gif, 14 ko]

Abbreviation : And
English name : Andromeda



This large constellation of the northern hemisphere belongs to the constellation family of Perseus. The name of the alpha star of Andromeda Sirrah (or Alpheratz) has been taken form the Arabic meaning "horse's navel". The reason for this is because in former times this star has been associated with the constellation of Pegasus, next to Andromeda. Nowadays it marks the head of the royal daughter.
Sirrah is a blue-white star (spectraltype B8IVpMnHg) with mag 2.06 .

Stars and other objects

The binary gamma And gives splendid view even in smaller telescopes for the two components can easily be separated. The brighter component has mag 2.2 whereas the fainter shows a brightness of mag 5.0 . As they are of different color they certainly make a showpiece of a double in the sky.
The 56 And is a fainter pair, both being of 6th magnitude.
The planetary nebula NGC 7662 is one of the easiest to view with smaller amateur instruments. Using a high magnification it reveals a fuzzy blue-green elliptical disk.
The stars of the open star cluster NGC 752 are scattered over a large area. Therefore it is best viewed with binoculars. The member stars (about 100) show magnitudes between 9 and 10. NGC 752 is located near 56 And.
This constellation is best known for the Andromeda Galaxy, M31, one of the most famous objects in the sky, which can most easily be found (it can be seen even with the naked eye once you get a bit out of a lightpolluted city) and gives a brilliant view in each optical instrument. As it is the nearest spiral galaxy to us, it allows therefore an intensive study of the properties of spiral galaxies. Because we sit within our galaxy we cannot so easily observe the properties of ours but the Andromeda galaxy helps to understand our galaxy as well.
The Andromeda Galaxy has two satellites: M110 (NGC 205) and M32. M110 is located one degree northwest of M31 and M32 can be found half a degree south of M31. Both are elliptical galaxies. Detailed information to all three galaxies can be found in the Messier database about M 31, M 32 and M110.

Mythological Background:

Long ago in ethiopia Andromeda has been the daughter of Cassiopeia and Cepheus. Unfortunately her mother was overbearing that she thought herself to be more beautiful than than the daughters of Nereus, a god of the sea. So Cassiopeia was hit by the anger and the revenge of the god Poseidon. To punish the mother, Andromeda was chained to a rock of the coast as a sacrifice for a sea monster. Yet she escaped this fate for she was saved from death by Perseus. For rescuing her he demanded Andromeda as his wife (which the parents gladly accepted). (Publius Ovidius Naso: Metamophoses, IV)

Andromède au Quotidien Etoiles & Galaxies Constellation d' Andromède
[Etoiles & Galaxies]

Updated : 24/10/99 Copyright AMatthieu :
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