23 February 2010

Winter Sky Show: Gemini, Mars and the Moon

Gemini is one of the finest constellations you can see during the winter months, easy to spot because it traverses the highest spot in the sky (the zenith) and features two bright stars, the twins Castor and Pollux. These two stars are well known because they symbolize the heads of the mythical twins. The stars that make up the rest of the bodies of the twins are less bright and require slightly darker conditions than we will have this week, but I provide an image nonetheless so you can see the rest of the stars when conditions permit.

Mars is the bright orange beacon of light that is gracing the night sky, the brightest object high in the sky for the next many weeks. As Mars orbits the Sun, we observe it moving against the backdrop of the Zodiac constellations, changing its position gradually from month to month as it travels eastward from our Earthbound perspective (this is called prograde motion, in contract to retrograde motion – more on that in a future post). It is about to start moving away from the twins of Gemini through Cancer toward Leo the Lion where it will arrive in May.

The Moon sweeps through this busy part of the sky, passing slightly south of Gemini, Mars and later this week the bright star Regulus in the constellation Leo. The bright Moon will drown out the background stars of these otherwise bright constellations, but the prominent stars Castor, Pollux and Regulus, along with Mars, will shine beside the waxing gibbous Moon. Binoculars or a telescope are a good idea if you want to see this close up!


Sidewalk Universe said...

Hey nice posting Urban Guy! You make this so easy for the average Joe.

Yes indeed with a few simple observations over a few weeks you too can see Mars traverse the skies and our beloved Luna over the month. These simple alignments of our Moon and the bright stars of the zodiac never fail to please.

I never get bored with this show.

Thanks for bringing this to your readers attention!

Sidewalk Universe said...

I am outside right now enjoying Luna dance her way through Gemini and closing in on a meeting with Mars. It is fun to see things shift across the sky in just a few hours time.

Wonderful terminator moon views tonight - never dull!

The Urban Astronomer said...

Just took a moment to show my daughter the sky this evening. It's a rare clear night in San Francisco (we've had an atypically cloudy and rainy winter). A sky like this is great for teaching the ecliptic and the path of the summer Sun.

I'm delighted that you were out to see this tonight, Richard. Tomorrow should be another fine night for bright-object observing!