Andromeda is a large and bright constellation of the northern hemisphere that represents the daughter of King Cepheus and Queen Cassiopeia. It is visible in fall and winter and best visible in the month of November, high in the evening sky.
Abbreviation: And Genitive: Andromedae English name: Andromeda
Notable Stars in Andromeda
Alpha Andromedae (Alpheratz or Sirrah) – This 2nd-magnitude star makes the head of Andromeda and the northeast corner of the Great Square of Pegasus. It is a spectroscopic binary with a period of 96.6 days and a luminosity of about 160 times that of the Sun.
Beta Andromedae (Mirach) – A 2nd-magnitude double star, easily resolved into its two components with a small telescope. It is located about 90 light years away from Earth.
Gamma Andromedae – A beautiful double star, easily resolved with amateur telescopes into its two components of magnitudes 2.2 and 5. The brighter star is yellow and the companion appears light blue.
Pi Andromedae – A double star approximately 660 light years from Earth. The brightest component has a magnitude of 4.3 and the companion is 9th magnitude, 36 arcseconds away.
56 Andromedae – A pair of 6th-magnitude stars, easily split with binoculars.
R Andromedae – A Mira type variable located about four degrees southwest of the famous galaxy M 31. Its brightness ranges from 5.8 to 14.9 in a period of 409 days.
RX Andromedae – A variable star belonging to the Z Cameleopardalis class. Its magnitude ranges from 10.3 to 14 in a period of 14 days.
Groombridge 34 – One of the closest double stars to Earth. Its two components are magnitudes 8.1 and 10.9, separated by 39 arcseconds.
Notable Deep Sky Objects in Andromeda
M31 (The Andromeda Galaxy) – One of the most famous objects in the night sky, and the most distant visible with the naked eye on a clear night. Seen through a telescope the galaxy appears as a small elongated patch of light, with a diameter of over four degrees.
Two more satellite galaxies lie nearby. The brightest of these is 9th-magnitude M32, located some 0.5 degrees south of M31. The other satellite is NGC 205, one-degree northwest of M31.
When observing use low power and a wide-field eyepiece, otherwise you won’t be able to fit the galaxy in the visual field.
NGC 752 – A bright and scattered open star cluster visible with the naked eye. It is composed of over 60 stars of magnitudes 9 and fainter. Seen with binoculars or small telescopes it appears as an obvious glow, with a sprinkling of a dozen or so stars in front. On closer inspection it is resolved into a swarm of stars, spread in a field of over 45 arc minutes.
NGC 891 – A spiral galaxy seen edge-on, located four degrees east of Gamma Andromedae. It is a difficult object for small telescopes because its surface brightness is pretty low, but on clear nights it is visible in a 4.5-inch scope.
NGC 7662 (The Blue Snowball Nebula) – An easy planetary nebula for small telescopes, located one degree west of the 4h-magnitude star Kappa Andromedae. At low power it appears as a nearly stellar object of magnitude 8.5. At high magnification the nebula’s blue disk becomes obvious, this object is a must see for all amateur astronomers!
Andromeda is associated with the Andromedids (Bielids) shower, which produced meteor storms in 1872 and 1885 when comet Biela broken up into two pieces. It seems that the Andromedids have now faded away, but some activity is still possible each year in mid- November. Current radiant position is RA 26 degrees, Dec +37 degrees.