Gamma¹ Andromedae

Gamma Andromedae, officially named Almach, is the third brightest star in the constellation of Andromeda. It is a member of a multiple star system of Almach. It is approximately 350 light-years from our Solar System.

The system consists of four members, Almach C, Almach Ba, Almach Bb and Almach itself.

Name
Gamma1 Andromedae (abbreviated to γ1 And) is the star's bayer designation, a stellar designation where a greek letter is followed by the genitive form of its constellation name. The small number one next to the letter signs that it is the primary star in a star system. However, Gamma Andromedae (abbreviated to γ And) itself is the name of the whole star system. Gamma Andromedae A are also acceptable.

Almach was the traditional name of Gamma Andromedae and it was (or Almaach, Almaack, Almak, Almaak, Alamak) derived from the Arabic العناق al-‘anāq which means "the caracal". Another term for this star used by medieval astronomers writing in Arabic was رجل المسلسلة (Rijlalmusalsalah), "Foot of The Chained Woman", the chained woman here refers to Andromeda.

In Chinese, 天大將軍 Tiān Dà Jiāng Jūn meaning Heaven's Great General, refers to an asterism consisting of γ Andromedae, φ Persei, 51 Andromedae, 49 Andromedae, χ Andromedae, υ Andromedae, τ Andromedae, 56 Andromedae, β Trianguli, γ Trianguli and δ Trianguli. Consequently, the Chinese name for γ Andromedae itself is 天大將軍一 Tiān Dà Jiāng Jūn yī which means the First Star of Heaven's Great General.

Astrologically, this star was considered "honourable and eminent."

Observation
In 1778, Johann Tobias Mayer discovered that Almach was a double star. When examined in a small telescope, it appears to be a bright, golden-yellow star next to a dimmer, indigo-blue star, separated by approximately 10 arcseconds. It is often considered by stargazers to be a beautiful double star with a striking contrast of color.

In October 1842, Wilhelm Struve found that Almach C was itself a double star whose components were separated by less than an arcsecond. The components are an object of apparent visual magnitude 5.5, Almach B, and a type-A main sequence star with apparent visual magnitude 6.3, Almach C. They have an orbital period of about 64 years. Spectrograms taken from 1957 to 1959 revealed that Almach B was itself a spectroscopic binary, composed of two type-B main sequence stars, Almach Ba and Almach Bb orbiting each other with a period of 2.67 days.

Position
The location of Almach in the sky is shown on the left. Almach is well overhead for observers in the northern hemisphere in the waning months of the year at about 9 p.m. It’s also visible from the populated parts of the southern hemisphere about 10-15º above the northern horizon at 8-9 p.m. local time in November and December.

To resolve this star, one will need a telescope as it is usually not visible with the naked eye. The pair is about 10 arcseconds apart. Even the smallest scope will do. Almach is located just at the edge of Andromeda's main body.

The coordinates of Almach is around 02h 03m 53.9531s, +42° 19′ 47.009″.