Star Points for March 2010 by Curtis Roelle
The Big Thaw

Now that the drifted banks of snow -- our souvenirs of this winter's blizzards -- are slowly melting 
away, let's turn our thoughts to what sights await us in the night sky.  If it's a clear night, why not 
step outside for some fresh cool air and see what you've been missing? You don't need a telescope 
for this tour.

Ever since the winter solstice in December, the sun has been riding higher in the sky each day and 
the nights are growing shorter. In early March the sun sets shortly after 6:00 p.m.  If you have a 
clear view of the western horizon, without any obstructing trees or buildings, make a note of where 
the sun sets along the horizon.  At 6:30 p.m., 30 minutes after sunset, come back out and have a 
look very low on the western horizon and see if you can spot the brilliant planet Venus.  As March 
goes on, the planet climbs higher in the evening twilight.  

By 7 p.m. the sky should be getting dark enough for the brighter stars to appear. You may be 
familiar with the standard winter constellations such as Orion and Taurus.  But in other cultures 
these same stars take on new meanings. 

Tonight the buffalo roams the sky in the form of the Lakota Sioux Native American constellation 
called the Bison.  Start by looking south and locating the constellation Orion.  Orion's belt is the 
spine of the Bison.  Betelgeuse and Rigel, the bright stars above and below the belt, mark the 
location of the left and right rib cages.  

Using the belt stars as pointers, follow them eastward (left) to the very bright star Sirius, located in 
the constellation Canis Major, the great dog. Sirius marks the end of the Bison's tail.  

Then using the belt stars as pointers once again, follow them (right) westward and up a little bit to 
the north, going about the same distance as Sirius is from the belt.  You'll see the star Aldebaran in 
the constellation Taurus, the bull.  Although not as bright as Sirius, Aldebaran has a distinct 
yellowish-orange cast to it.  Aldebaran marks Bison's neck hump.  

Continuing past Aldebaran the same distance Aldebaran is from the belt, you'll come to a small 
knot of stars know to the Lakota as the Seven Girls, also known as the Seven Sisters and, by 
astronomers, as the Pleiades star cluster. The Pleaides mark the location of Bison's wooly head.

So now you've learned a new constellation. Not one of the "official" 88, but an important one in 
American culture. 

Now let us look for some more naked-eye planets.  Nearly straight overhead around 9 p.m. is the 
planet Mars. It is distinguished by its unique ruddy orange color.  Mars was at its closest to earth in 
late January.  Although it's now dimming a little, it remains easily visible.   

The final planet on our tour is Saturn, rising in the east-southeast.  It will look whitish-yellow and be 
fainter than Mars.  You may be able to confirm it's really Saturn by using a pair of binoculars to 
spot the elongation of the rings.  

If you have a telescope, this would be a good time to get it out.  Of course, you may wish to wait an 
hour or two for Saturn to climb higher in the sky, where there will be less distorting atmosphere for 
the telescope to peer through. Starting with the lowest power eyepiece, notice the elongation of the 
rings. If conditions allow, step up to the next higher power eyepiece.  Look for any shadows – the 
shadow of the rings cast on the planet's surface, and the shadow of the planet falling on the rings 
behind it. If the view isn't very satisfactory, don't be afraid to return to the lower power.