Fireworks Prelude

The night of July fireworks, as the crowd gathers and darkness settles in, eyes are looking skyward in anticipation of a spectacle.  Appropriately, America’s Semiquincentennial Star is among the first to appear in the deepening twilight.  

The day our founders were signing the Declaration of Independence, light left the star Spica in the constellation Virgo.  Traveling at 186,000 miles per second, those photons are just now striking our retinas, for Spica is 250 light years away.  As we have ventured through 250 years of American history, Spica’s light has concurrently zipped through 1.5 quadrillion miles of space.  

Spica is a bright, first-magnitude star that appears in the lower southeast sky in July.  Actually a closely bound pair of stars, their combined brightness is 1,900 times more luminous than the sun.  To find Spica, first locate the Big Dipper, a prominent grouping of seven stars in the northwest.  From the curved handle of the Big Dipper, follow the arc to the bright yellowish star Arcturus and then drop down to Spica.  

During July fireworks, follow the arc to Arcturus and spike down to Spica. From Arcturus, go up to find Corona Borealis,

Two other celestial highlights are in the same chunk of sky this year.  First, brilliant Venus is prominent in the west.  Perhaps you earlier saw Jupiter down and to its right shortly after sunset. 

Second, above Arcturus is the U-shaped constellation of Corona Borealis, the Northern Crown.  Its lower left bend is the site of a recurring nova, which astronomers predict will erupt again within the year.  It’s one of only two known recurring novae visible to the naked eye.  Since you’re outside at night awaiting fireworks, with your cell phone camera take a 10-second exposure of Corona Borealis now so you can compare it to the same starfield after the nova appears.  The last time anyone saw this recurring nova was 1946, and it will likely be another 80 years before it blows up again.  

For added effect, see if you can get a photo of America’s Semiquincentennial Star and pre-eruption Corona Borealis with fireworks in the foreground.  Now that would be a spectacle.