Designations
- Bayer: γ Dra
- Flamsteed: 33 Dra
- Hipparchos: HIP 87833
Data
- Constellation: Draco
- Apparent Magnitude: 2.23
- Right Ascension (J2000): 17h56m38.09s
- Declination (J2000): +51°29'30".9
- Colour Index (B-V): 1.53
- Distance: 154.28±0.73ly
Description
The star γ Dra is of particular note in Draco, but not because it is the brightest of the constellation. The star was nicknamed 'the birth-star of modern astronomy' by English Astronomer Royal Sir George Airy because it, along with HD 40873 (which was given the designation of 35 Cam despite lying within Auriga), was the subject of James Bradley's observations that led to the discovery of the aberration of light, which in turn provided observational proof of the heliocentric solar system model.
In most depictions, this star lies at the top of the head of Draco, in accordance with Ptolemy's description.
Nomenclature
Eltanin
The name is simply from the sci-Arab title for the star, Ra’s al-Tinnīn, 'the head of the serpent', corrupted and abbreviated in Renaissance times to Eltanin.