Andromeda Constellation
Andromeda constellation
The object to the right of the constellation is the Andromeda galaxy.
Andromeda Constellation Facts
  • Andromeda is visible in both the Northern and Southern hemispheres.
  • In the Northern hemisphere Andromeda can be seen from August to February.
  • In the Southern hemisphere the constellation can be viewed from October to December.
  • The Andromeda galaxy, which lies within the constellation, is the furthest object that can be seen with the naked eye, it is 2.5 million light years from Earth.
  • The Andromeda galaxy is orbited by several smaller galaxies, some of which are visible through a telescope or binoculars.
  • Alpheratz is the brightest star in the constellation and also forms part of the Square of Pegasus asterism.
  • Andromeda is part of the Perseus group of constellations which also includes Cassiopeia and Pegasus.
  • The Andromedids meteor shower which occurs every November is named after Andromeda as it appears to emanate from the constellation.
  • Andromeda is one of the original constellations listed by the Greco-Roman scientist Ptolemy almost 2,000 years ago.

Andromeda Mythology

Andromeda mythology
Princess Andromeda hurtling across the night sky in a rather unflattering pose.
Princess Andromeda is a character from Greek mythology, she was famed for her beauty and would eventually marry the hero Perseus. Andromeda’s mother was Queen Cassiopeia, she was also known famously for her beauty but infamously for her vanity. Her vainness would eventually upset the gods and a sea monster was dispatched to destroy her kingdom. The queen and her husband King Cepheus thought the best thing to do would be to chain their daughter Andromeda to a rock as an offering to the sea monster. Luckily Perseus was there to save the day, he freed her from her chains and killed the monster.
The pair married shortly after and settled in Perseus’s home island, during their marriage they had a total of nine children together. After her death Andromeda was placed in the heavens alongside her husband Perseus and mother Cassiopeia. Andromeda’s image appears mainly upside down in the night sky but there is no reference in to her actually being placed there in such a fashion.

Main Stars and Objects in the Andromeda Constellation
Andromeda constellation
The number next to each star is its apparent magnitude, its brightness from our point of view on Earth, the lower the number the brighter the star in the night sky.
Almach
Also know as Gamma Andromedae, Almach is actually a triple star system around 350 light years from Earth, the primary star is an orange giant around 80 times larger than our sun.
Mirach
Also known as Beta Andromedae, Mirach is a red giant around 200 light years from Earth, it has a mass around 4 times greater than our sun and is 100 times larger in size, Mirach is occasionally the brightest star in the constellation but as its brightness is variable it isn't officially considered the brightest star.
Alpheratz
Also known as Alpha Andromedae, Alpheratz is actually a binary system consisting of two stars orbiting each other, the primary component is a blue star with a radius 3 times greater than our sun with surface temperatures more than twice as hot. Alpheratz is officially the brightest star in Andromeda, it is also considered as part of Pegasus as it connects both constellations.
M31
The most interesting object in the constellation is undoubtedly M31, otherwise known as the Andromeda Galaxy. Even though this galaxy is 2.5 million light years from Earth it is brighter than many stars in the night sky and is easily visible to the naked eye. The Andromeda galaxy is larger in size to our own Milky Way galaxy but may be less massive.

Finding Andromeda - Northern Hemisphere
finding Andromeda northern hemisphere
The chart shows the position of Andromeda over most of the United States in December at 8pm. This chart can also be applied to other areas of the Northern hemisphere such as Canada, the UK and Europe.

From August to September Andromeda will first appear low on the north-eastern horizon around 10pm, over the next 6 to 7 hours it will climb higher in the sky reaching overhead before day breaks.

From October to November the constellation will be visible in the eastern sky around 8pm, by midnight it will be directly overhead before heading towards the north-western horizon.

From December to January it will appear overhead at around 6pm gradually moving towards the north-western horizon as the night moves on.

In February Andromeda will be visible in the western sky from around 7pm before disappearing below the north-western horizon by midnight.

Finding Andromeda - Southern Hemisphere
finding Andromeda southern hemisphere
The chart shows the position of Andromeda over most of Australia in late autumn at midnight. This chart can also be applied to other areas of the Southern hemisphere such as New Zealand, South Africa and South America. In the Southern hemisphere Andromeda is visible in the northern night sky.

In October and November Andromeda becomes visible at around 10pm low on the north-eastern horizon, over the next few hours it will gradually move towards the north-western horizon staying low in the sky.
In December the constellation will appear low on the northern horizon at around 10pm before disappearing below the north-western horizon by around 1am.


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