Where is the constellation Gemini? Its brightest stars stand out at magnitudes between +2 and +1, but don’t confuse them with the two brightest stars in Canis Major or Canis Minor, which are also nearby. Here’s part 2 of my 12 video series on the Zodiacal constellations. Let’s draw upon Gemini to see what we can learn about the night sky!
When to Find Gemini
I was able to take a picture of Gemini in January. During December, January, and February you’ll be able to see Gemini pretty much all night. Because of the earth’s rotation, the constellations are constantly moving across the sky. So of course, finding any constellation depends on what time you’re looking. At the beginning of February, Gemini Rises in the eastern horizon at about 3 pm, so by the time it’s dark you will be able to see him fairly high in the eastern sky. This is nice because if you’re near somewhere with obstructions like mountains or buildings that block the eastern horizon, then you wouldn’t be able to see Gemini until a couple of hours after it rises anyway.
Who is Gemini
Gemini is Latin for “Twins.” You may have seen Gemini represented as female, but in the Greek tradition they appear as twin brothers. Actually twin half-brothers. Pollux was said to be the son of Zeus, while Castor was the son of the King of Sparta. Both were born of Leda, the queen of Sparta.
Where to Find Gemini
Gemini rises in the east just after Taurus, the bull. To find Gemini, look for two bright stars (Castor and Pollux) just east of Orion or Taurus. You could draw a line in the “V” asterism of Taurus, through Aldebaran, to find it.
Brightest Stars
Castor And Pollux are the names of the two brightest stars in Gemini, and as discussed the names of the twins from Greek mythology. Castor is the first of the two to rise above the horizon. It also has the designation Alpha Geminorum, (alpha being the first letter of the Greek alphabet), which generally marks the brightest star of the constellation, but it’s actually the second brightest star in Gemini.
Pollux (just below Castor), or Beta Geminorum, claims the title of Gemini’s brightest star. In 2006, Pollux was confirmed to have an extrasolar planet. (Extrasolar being the term used to describe any planet outside of our star system — Extra meaning beyond or outside, and Sol being the name of our star.) You can remember which star is which by remembering their names are in alphabetical order: “C” comes before “P,” as does Castor rise in the east just ahead of Pollux.
When you find Gemini, you will see Castor and Pollux easily because they’re so bright, although there are supposedly a total of 85 stars visible to the naked eye in this constellation. Even in low visibility, though, I can usually distinguish at least the 17 stars that are connected to the lines represented by the International Astronomical Union. Visibility of course depends on weather conditions and light pollution. And I should point out, look for this curve shape of Castor’s leg to confirm you’re not looking at Canis Minor, which has a similar set of two stars and is nearby.
Celestial Objects in Gemini
There is an open star cluster named Messier 35, which is about the size of the full moon, near Caster’s leg. Under a dark sky and good conditions, it can be seen with the naked eye. However, with any light pollution around it will be hard to see.
With telescopes, you should also be able to spot a couple of notable nebulae nearby. NGC 2392 and the Medusa Nebula. These are both planetary nebula, a type of nebula formed by dying stars ejecting ionized gas.
Conclusion
Thanks for reading! I hope you have clear skies tonight, so you can check out Gemini and maybe even see M35—that open star cluster near Castor’s foot. Leave your comments and questions on my Youtube video, and subscribe so you don’t miss my new videos.
Have a good day and remember to smile!
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