Spring evenings find Orion the Hunter stumbling toward the western horizon.  Most northern observers will find Rigel, the bright star in Orion’s toe, dropping below the horizon before the sky is completely dark.  Betelgeuse, the reddish star in his shoulder, will set an hour and a half later.  Sirius, the brilliant star just left of the Hunter, will disappear around 10:30.

As Orion slips into bed, a bright blue-white star climbs in the northeast.  That’s Vega, almost exactly the same silver-white color as Sirius but only about a quarter as bright.  Shortly after Vega rises, Deneb will rise to the left, in the east-northeast.  Shortly after midnight, a third bright star, this one on the right, will climb above the trees.  These three, Deneb on the left, Altair on the right, and Vega high in the center, are the Summer Triangle, signaling the arrival of cool nights and warm(er) days.

Altair is the heart of Aquila the Eagle, a constellation that requires a bit of imagination.  Try to visualize the Eagle’s body and tail on the right and stars above and below Altair as wings.  Cygnus is easier:  picture Deneb as the tail of a swan with its long body and neck stretching to the right and wings spread to the sides.  The intersecting lines of stars also give it the unofficial modern name of the Northern Cross.

Vega is the brightest star in the constellation Lyra the Lyre.  Most people do not carry lyres on their daily sojourns and find it easier to imagine Lyra as a diamond ring.  A parallelogram of four stars outline an oblique view of the ring while Vega provides a flash of light from the diamond.  Next to Vega, the other corner of the diamond, is the star Epsilon Lyrae which, in a very clear dark sky, keen-eyed observers may see as a double star; if the sky is a bit hazy, binoculars will easily reveal the separate blue-white points of light.  A small telescope will reveal even more:  each component of the double star is itself a double star, leading Epsilon Lyrae to be known as the Double Double.

Lyra has other distinctions, one of them tied to this month's calendar.  The Lyrid meteor shower, in which meteors appear to stream from a point just outside the diamond ring, will peak on the morning of Monday the 22nd.  Even in good years, this is not one of the better showers and this year the display will compete with the glare of a bright gibbous moon.  Nevertheless, the Lyrids can sometimes be surprising and are always a good excuse for taking in the beauty of a star-filled sky.  Take a look outside on any evening around the 21st or 22nd or any time you might fancy a diamond ring in a clear dark sky.


NASA’s website on the Lyrids includes a sky map at <http://spaceweather.com/meteors/lyrids/lyrids.html>.


           Keep looking up!
           - Bob Hamlin
               <rhamlinatdartmouth.edu>

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