Goodbye Venus, Hello Saturn

Venus has dominated the evening sky for so long, it’s going to seem a little bare in the west as the ‘evening star’ sets with the Sun. Venus will pass between the Earth and Sun on March 27, and it won’t be long after that before the ‘morning star’ blazes into the predawn sky.

High in the southern sky as the sky darkens is mighty Orion the hunter. The seven brightest stars stand out, even if your sky is not completely pitch black. Orion is especially easy to find because of the three stars in a row marking the belt around his waist.

On a clear, dark, moonless night, look for the fainter stars of Orion. He is carrying a battle club above his head, a shield on his other arm, and a small sword on his belt.

Orion can point the way to other winter constellations. Draw an imaginary line through the three stars in Orion’s belt, down toward the southeast. You’ll run into Sirius, which is also known as the ‘dog star’ because it lies in Canis Major the big dog. Sirius is the brightest star we can see in the night sky, but it is not as bright as Venus currently in the west.

There is also a little dog, Canis Minor, but there are only two reasonably bright stars to find. Even on our star chart, Canis Minor is just a line from Procyon to a fainter star.

Draw a line through the stars in Orion’s belt up, toward the northwest, and you quickly encounter a v-shaped group of stars marking the face of Taurus the bull. Aledebaran represents one eye, with the point of the v indicating the tip of the bull’s nose. Extend the small v to create a large V, and you’ll find the tips of the bull’s long horns.

Continue the line from Orion’s belt through the face of the bull until you reach a small cluster of stars known as the Pleiades. Even though they are often called the ‘seven sisters’, only six stars are visible to the unaided eye. The Pleiades make an excellent target for binoculars. More than one hundred brilliant points of light stand out against the inky blackness of the sky beyond.

A surprising number of people see a tiny kite or little dipper in the Pleiades. The real Little Dipper is actually located in the northern part of the sky along with the Big Dipper. Spring is the best time to look for the dippers because they appear high above the northern horizon after sunset.

The seven stars of the Big Dipper can be seen even with some light pollution, but the stars of the Little Dipper are much fainter. You will have to hunt for Polaris or the two stars on the outside of the bowl. Consider the Little Dipper a ‘challenge’ object, and please do not give up stargazing if you cannot see it from home.

With Venus exiting the evening scene, Saturn is the only planet visible after sunset. Saturn appears as a faint dot just below Leo the lion. It’s not as bright as usual because from Earth, we are currently seeing the rings edge-on. As Earth and Saturn orbit the Sun, this alignment happens roughly every fifteen years. Without the reflected sunlight from the surface of the rings, Saturn is much dimmer than usual.

Turn Out The Lights!

The next FREE public star party is set for Saturday, March 28, 2009, from 8:00 - 10:00 PM, at Adventure Science Center.

March 28 is the night of Earth Hour. From 8:30 to 9:30 pm in each time zone that night, cities around the world are encouraged to shut off non-essential lights to demonstrate their commitment to energy conservation. Nashville is one of the key cities involved in this event.

Adventure Science Center has one of the best views of the Nashville skyline. Members of the Barnard-Seyfert Astronomical Society will be on hand to show off beautiful sights in the night sky as we watch the city lights wink out all over downtown.

With less light pollution from the city, will we be able to see more stars? Join us and find out. Don’t forget to turn out your lights before leaving home! To learn more about Earth Hour, visit earthhourus.org/nashville/. Be sure to check our star parties page, where you can also find helpful tips for enjoying a star party. If it is cloudy or raining, the star party will be canceled. If the weather is questionable, visit our web site or call AstroLine at (615) 401-5092 before leaving home.

Measuring the Night Light

Light pollution is a common problem for both professional and amateur astronomers. Light spilling upward from streetlights, billboards, security lights, and other sources make it hard to see any but the brightest stars in the night sky. The further you are away from light pollution, the more stars you’ll be able to see.

How dark are your skies? Participate in the GLOBE at Night program and find out. The dates for the event are March 16-28. Go out on at least one of these nights to count the stars you can find in the constellation Orion. Compare the stars you can see to a chart you can download from the GLOBE web site at www.globe.gov/GaN/.

Most importantly, report your results back to GLOBE, which will construct a map of light pollution around the world.

Note that Earth Hour falls during the last evening of GLOBE at Night. Turn off your outdoor lights and see if your results change!

So what’s the message of Earth Hour and GLOBE at Night? That we should all get rid of all our lights? No! We need good lighting to see where we’re going and to be safe at night. But good lighting doesn’t have to spill light up into the sky. It’s a waste of electricity, and it ruins our view of the stars. To learn more about light pollution, visit www.darkskysociety.org.