SkyEye: Gemini

The Twins

Abbreviation:	Gem
Genitive:	Geminorum
Origin:	[antiquity]
Fully Visible:	55°S – 90°N

Gemini is a member of the zodiac. This is one of the most ancient of constellations, harking back to Babylonia where the stars Castor and Pollux were known as the Great Twins. In Greek mythology, this constellation is associated with the twin brothers Castor and Pollux. Their mother was Leda but Castor's father was the mortal Tyndareus, the king of Sparta, and Pollux's father was the king of the gods, Zeus. Zeus placed them in the sky after Castor was killed; thus the brothers are together forever.

The constellation of Gemini

Notable Features

Visible Named Stars
α Gem	Castor	Although it appears as a binary through a small telescope, Castor is actually a six-star system. It appears as Aoul al Dzira (from the Arabic awwal al‑dhirāʿu meaning 'the first in the forearm') in Mohammad Al Achsasi Al Mouakket's calendarium. In Hindru astronomy, α Gem and β Gem together are known as Punarvasu, from the Sanskrit punarvasu meaning 'the two restorers of goods'.
β Gem	Pollux	Although the β (beta) star in the constellation, first-magnitude Pollux is actually the brightest star in the constellation. It is known to have at least one exoplanet. It appears as Muekher al Dzira (from the Arabic al‑muʾakhkhar al‑dhirāʿu meaning 'the last in the forearm') in Mohammad Al Achsasi Al Mouakket's calendarium.
γ Gem	Alhena	This second-magnitude star is a spectroscopic binary.
δ Gem	Wasat	The dwarf planet Pluto was discovered near this star in 1930.
ε Gem	Mebsuta	At third-magnitude, this is one of the brighter stars in the constellation.
ζ Gem	Mekbuda	This is a Cepheid variable with a period of around 10 days.
η Gem	Propus	This star sometimes appears as Tejat Prior in older star atlases and catalogues. In Chinese astronomy, this star is known as Yue, from Yuè meaning 'the battle axe'. William Herschel discovered the planet Uranus on 13 March 1781 near this pulsating red giant.
μ Gem	Tejat	This star sometimes appears as Tejat Posterior in older star atlases and catalogues.
ξ Gem	Alzirr	This third-magnitude star exhibits high proper motion.
ο Gem	Jishui	Unlike many of the star names in this constellation, this one has its origins in China.
Other Interesting Stars
PSR B0633+17	Geminga	This unusual neutron star is a gamma-ray and X-ray pulsar. It was discovered in the 1970s.
Deep Sky Objects
M35		This is an open star cluster which is easy to see through binoculars.
C39		This famous planetary nebula, also known as NGC 2392, is just visible through a small telescope.
Meteor Shower Radiants
004 GEM	Geminids	These December meteors are of average speed and brightness but the Geminid meteor shower is one of the richest in the calendar, peaking at over 100 meteors per hour. The parent body is not a comet but an asteroid, 3200 Phaethon.