The Spectacular Winter Circle

Winter brings out the best in the night sky. Some of the finest stars in our galaxy are concentrated in a region of the sky that shines with an intensity that you just can't miss on a clear night. A collection of extremely bright stars form a nice shape that is fun to look for, the Winter Circle. This asterism features 5 of the 8 brightest stars in the entire night sky, and in total 7 very bright stars that glow in the south on long winter nights.

The Winter Circle

Given that all of the stars in the Winter Circle are bright, this is a relatively easy target for city dwellers who might not normally pay attention to the night sky. The stars are part of six different constellations covering a fairly significant part of the winter sky. January evenings feature the Winter Circle moving gradually from east to west across the southern horizon. Given the span of this asterism from the lowest point at the star Sirius (see diagram) to the highest point at the star Capella, you will need a fairly clear view across the southern sky. For me, it's easy to spot one or two constellations wherever I am, but seeing all six constellations and all 7 of the bright stars in the circle requires that I have a good horizon and not much else blocking the way.

Most people can quickly and easily find the constellation Orion, and from there you can start your trip around the circle. Rigel is a blue supergiant star that is one of the kneecaps of the hunter Orion, and it is one of my favorite stars because of the intensity and color. Orion's 'belt' can help you find two other members of the circle, by following the belt up toward Aldeberan and down toward Sirius. The other stars are then easy to find looking up and left of Orion toward Gemini, Auriga and Procyon.

Finding a wide open space on a clear winter night where the grandeur of the Winter Circle is on full display is one of my favorite things. The stars are rich and intense, and the utter size of the circle make the viewing of this amazing pattern worth the effort. Dress warm and savor the moment. You will be glad you made the effort.

Image courtesy of SkySafari.

Update: good article from Sky & Telescope on the Winter Circle. They call it the Winter Hexagon.

Bright Stars and Planets in the Morning

Fantastic Morning Sky

I get up early, and I am quite aware of the fact that as autumn begins, the mornings are darker and darker. Here in the west side of San Francisco, autumn is when our clear skies return (following the summer fog) and the sky starts to come alive. My early start of the day means that I get to see the fabulous winter skies and the brilliant planet Jupiter when I step outside to get the newspaper. The southeasterly view just before dawn is riveting, with Jupiter dominating
the sky to the east, and the stunning constellation Orion, and the brightest star in the sky Sirius, to the south.

Later this week, the waning gibbous Moon glides high across the sky, passing near Jupiter on the 28th. As the sunrise moves a few minutes later each morning, the sky becomes more accessible and if you can spare a minute of your morning routine, you'll like what you see.

Image courtesy of Sky & Telescope.

Alignments in the City Sky

Jupiter, Orion, and Sirius

I am viewing the sky this evening from one of the most densely populated urban areas, Manhattan. Looking up at the night sky here, you can't see many faint stars, but you can still see plenty of the brighter ones. Tonight looking toward the south, I was easily able to spot the fantastic alignment of Orion's belt, pointing downward toward the brightest star in the sky, Sirius, and pointing upward to the brightest planet in the sky in the evening, Jupiter. As Jupiter gradually moves in its orbit around the Sun, it will soon move out of alignment with Sirius, Orion's belt, and the bright star Aldeberan in the constellation Taurus. By the middle of 2013, Jupiter will be well on its way to the next sign in the Zodiac, Gemini. But for the coming weeks, you can enjoy the bright celestial alignment that can been seen from just about any location on Earth, even in the middle of an urban jungle such as NYC.

Image courtesy of Sky Safari.

KFOG Podcast - January 20, 2011

My monthly conversation with KFOG Morning Show's Irish Greg moved from the new Zodiac signs (such as Ophiuchus) to the Aurora Borealis to the big bold winter constellations such as Orion and bright stars such as Sirius. Click here to listen and get inspired to look up at the sky tonight!

Winter Triangle

One of the highlights of the winter sky is the Winter Triangle. This shape is a nearly perfect equilateral triangle that shines in the southern sky over the next few months. It includes three of the most brilliant stars in the sky, and it is called an "asterism" because it is not a single constellation, but a combination of stars from three different constellations.

The first and brightest star is Sirius, the brightest star in the night sky. Sirius is close to the Solar Systems (8 light years) and has a slight blue coloration. Sirius is in the constellation Canis Major, the big dog that accompanies Orion. To the upper right is Betelgeuse, a red supergiant star in Orion that is a distinctive orange color. Betelgeuse is so big that if it was our Sun, it would envelop Mercury, Venus, Earth and Mars! And the third star of the triangle is Procyon, in the constellation Canis Minor, the small dog that accompanies Orion. Procyon is actually a double-star system with a faint partner star.

Inside the Winter Triangle you can find numerous clusters of stars. I spent some time looking here a few nights ago and was able to see quite a few of these clusters, even in San Francisco. My backyard has a dark western horizon so by looking through binoculars later in the evening I was able to see quite a bit in and around the asterism. Try this for yourself sometime soon.