The constellation of Gemini is great to look for on a nice clear night during January and February as it’ll be overhead to the South. By the time it’s May, Gemini will be on the Western horizon as the Sun sets and through the northern hemisphere summer it’s up during the day.
The ‘twins’ are easily identified as two bright points of light close to each other. If you can find one of the most recognisable constellations in the winter sky, Orion, use the reddish star Betelgeuse to travel up and to the left to find the brothers. Click on the image below to embiggen and see more clearly.
Castor and Pollux are the twins of Greek mythology who both ultimately were gifted immortality in the heavens by their father Zeus. Castor (to the right side of the constellation) is a second magnitude star, whilst Pollux (to the left) is a first magnitude star. The remaining stars go to make up the united bodies of the twins.
Although when looking at Gemini, you are looking away from the core of the Milky Way, there’s still interesting things to be found such as the Eskimo Nebula and the Medusa Nebula – both planetary nebulae. Despite not being visible to the naked eye, these faint objects do provide lot’s of pretty pictures for more powerful telescopes to take 🙂
Around mid-December every year, Earth enters the debris trail left behind by asteroid 3200 Phaethon and observers on Earth are treated to the Geminids.
These meteors appear to radiate from the constellation of Gemini (in particular from close to the star Castor (the ‘twin’ of Pollux).
The asteroid debris is comprised of very small pieces of dust and rock (think not much bigger than a few grains of sand) that burns up in the Earth’s atmosphere providing us with a bright trail of light in the sky – a meteor!
Although the Geminids arise from the trail left by an asteroid, most meteor showers actually arise from the trail left by comets.