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  • Writer's pictureCelestial Events SA

Gemini - Constellation of the Month

Updated: Apr 5, 2020


Gemini has been known since Babylonian times where it represented 2 warriors guarding the gates of the Underworld. The theme of twins is found throughout different cultures with the Egyptians seeing them as twin goats, while the Arabs noted a pair of peacocks. The most famous mythology refers to Greek heroes, Castor and Pollux.

According to the Greeks, Gemini represents the twins, Castor and Pollux. One day Zeus saw the Spartan Queen, Leda, and hatched a plan to seduce her. He disguised himself as a swan and Leda was so taken by its beauty that she gave herself to Zeus. Leda also made love to her husband, Tyndareus, the same night and fell pregnant to both.

She later gave birth to 2 eggs. 1 egg contained the mortal Castor and his sister Clytemnestra, fathered by Tyndareus, while the other housed Zeus’s immortal children, Pollux and Helen (of Troy).

The brothers were inseparable and went on many adventures together, including joining Jason and the Argonauts in their quest for the Golden Fleece. During one trip, Castor was killed and Pollux was so distraught at the loss of his brother that he begged Zeus to allow them to be together again. Zeus obliged by placing them both in the heavens for eternity.


Gemini contains 2 notable stars named after the Greek heroes, Castor and Pollux.

Castor is the 23rd brightest star in the sky but the fainter of the 2 twins. Despite being dimmer, Castor is actually a 6 star system of 3 binary stars all orbiting a common centre. With a telescope, Castor can be split into 2 stars but the rest of the system is too faint for amateur equipment.

Pollux is an orange giant and the brighter of the 2 famous stars of Gemini. The 17th brightest star in the sky is easy to find on account of its red colour. Pollux has used up most of its hydrogen and has evolved into the red giant phase of its life, ballooning to a size nearly 10x the diameter of our Sun. At approximately 35 light years away, Pollux is the closest ‘giant’ star to our Sun.


Messier 35 is an open cluster containing a few hundred young stars that is visible with binoculars and amateur telescopes and takes up about the same space as full Moon.

M35 is situated very close to another compact open cluster known as NGC 2158 that presents like a loose globular cluster. M35 can be found amongst the ‘feet’ of the northern twin.

The Eskimo Nebula is a planetary nebula located in Gemini. It can be spotted about half way betwene an imaginary line drawn between Pollux and Procyon, the brightest star in Canis Minor.

Also known as the Clown Face Nebula, this object is the remnant of a dying star similar in size to our Sun. The layers of gas are leaching into space and manifest with a bluish/green tint that can be seen in telescopes of apertures of 6” and above.

The Eskimo Nebula is relatively young, at only 10,000 years old and will soon dissipate into space leaving nothing behind except a White Dwarf, the stellar corpse at its centre.

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