The bright gibbous moon appears Friday night in the zodiacal constellation Gemini. Gemini is a cold winter constellation. When Gemini, a constellation depicting twins, is high in the early evening sky, we are the subject to the wind of winter.

Gemini and the moon will rise a few hours after sunset. Gemini is one of our favorite constellations for double stars, star clusters and nebula.

Use the moon to guide you to this interesting constellation. Two of the brightest stars near the moon are Castor and Pollux. Pollux is the brighter of the two and is only 33 light years away, compared to the more distant Castor.

Castor is 52 light years away and is far more interesting as it is really six stars. With a low power telescope, Castor is two bright stars and they are caught in orbit together, like two dancers on the floor. It takes them 510 years to complete one revolution, a slow dance.

Using high technological equipment, astronomers discovered that at least one of those stars is really four. Castor is more like a family spinning together on the dance floor.

Wait a week or more for the moon to exit from this area of the sky and look at Gemini again. The bottom of Gemini is in the thick of the Milky Way cloud. There are so many stars to see in this interesting constellation without looking hard.