Gamma Draconis

Gamma Draconis (γ Dra, γ Draconis) is the Bayer designation for a star in the northern constellation of Draco. It has the traditional name Etamin or Eltanin and the Flamsteed designation 33 Draconis. Despite its gamma designation, it is actually the brightest star in Draco at magnitude 2.4, outshining Rastaban (Beta Draconis) by nearly half a magnitude. Its proximity to the zenith point directly overhead of London has earned it the name "Zenith Star." As for other places, it is relatively easy to locate in the night sky. If one finds Vega, Eltanin is the red star just north-northwest of it.

Eltanin lies around 154.3 light-years (47.3 parsecs) away, as determined by parallax measurements from the Hipparcos astrometry satellite. In 1728, while unsuccessfully attempting to measure the parallax of this star, James Bradley discovered the aberration of light resulting from the movement of the Earth. Bradley's discovery confirmed Copernicus' theory that the Earth revolved around the Sun.

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