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Identify the Winter Circle and winter’s brightest stars

2015-jan-30-orion's-belt-winter-circle-winter-triangle-moon-night-sky-chart

Tonight for January 30, 2015

Tonight’s chart covers a wider area of sky than we typically show. It’s in answer to a reader in Nashville, who wrote:

I’ve heard mention of the Winter Circle of Stars. Could you list the stars in this circle?

If you’re in the Northern Hemisphere, you’ll find these stars at this time of year by looking southeast at early-to-mid evening, and more southward from mid-to-late evening. Although the almost-full waxing gibbous moon shines within the Winter Circle tonight, all the stars of the Winter Circle (sometimes called the Winter Hexagon) are first-magnitude stars, so they should be able to withstand tonight’s drenching moonlight. Note also that the Winter Triangle – formed by bright stars Sirius, Betelgeuse and Procyon – make up the southeast part of the Winter Circle.

By the way, in 2015, a super-brilliant starlike object sits outside the Winter Circle, low in the east at nightfall. That object is actually the king planet Jupiter. This world is far brighter than any Winter Circle star. Watch for the moon to leave the Winter Circle after a few more days, and to pair with the planet Jupiter around February 3.

Back to the Winter Circle. It’s a humongous pattern of stars and covers a wide area of sky, but it helps to start out small – in this case, by finding the prominent constellation Orion the Hunter. Orion is very noticeable on these winter evenings (see chart at top of page). If you pick out any pattern of stars in the southeast at nightfall, it’ll probably be part of Orion.

The Winter Circle stars surround Orion. They don’t form a perfect circle … is anything ever perfect? Try starting at Capella and moving clockwise to Aldebaran, Rigel, Sirius, Procyon, Pollux, and Castor.

This pattern of stars is not a constellation. It’s a lot of separate stars in different constellations. In other words, it’s what’s called an asterism. From our Northern Hemisphere locations, these same bright stars can be seen before dawn every late summer and early fall. And they can be seen in the evening every winter. Hence the name Winter Circle.

I wonder what these same stars are called in the Southern Hemisphere? They’re visible from there, but of course it’s summer there now. I don’t know if this particular collection of bright stars has some special name as seen from that part of the globe. If any of you do know … tell us in the comments!

By the way, the ruddy star Betelgeuse, in the shoulder of the constellation Orion, isn’t part of the Winter Circle. But it is part of the Winter Triangle, which is inside the Winter Circle.

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View larger. | The Winter Circle as photographed by EarthSky Facebook friend Zhean Peter Nacionales in the Philippines. Thank you, Zhean!

Bottom line: The stars of the Winter Circle may be found in the sky now. It can be seen on these cold winter nights until well after midnight.

Read more about the Winter Circle: Brightest winter stars

Live by the moon with your 2015 EarthSky lunar calendar!