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June 29, 2006: This drives astronomers crazy. Every
summer, on the one night when millions of Americans are guaranteed
to be outside at nightfall, necks craned upward watching the
sky, almost no one pays attention to the heavens. It's all
fireworks, fireworks, fireworks. Stars and planets don't stand
a chance.
 But
this 4th of July is different.
At
sunset, just as the fireworks are about to begin, the Moon
and Jupiter will pop out of the twilight side-by-side: sky
map. These are the brightest objects in the night sky,
easily beaming through the flash and smoke of a fireworks
display.
Right:
The Moon and Jupiter side by side in May 2006. Photo credit:
Jason A.C. Brock of Wichita Falls, Texas.
Sidewalk
astronomers, deploy your telescopes! Here is a wonderful opportunity
to show off Jupiter's moons, the Great Red Spot, lunar craters
and mountain ranges, and the long creeping shadows at the
Moon's day-night divide. Bonus: Point your telescope at blank
sky and wait for some fireworks. A good starburst at 25x magnification
can be very entertaining.
And
don't forget to watch out for spaceships.
During
the first week of July, the International Space Station (ISS)
passes over many US cities in plain view of evening sky watchers.
July 4th is one of the best nights of all. Visit NASA's Sky
Watch web site to find out exactly when the station will
appear over your hometown.
To
see the ISS, simply look up at the appointed time. The station
moves slowly across the sky, glowing about as brightly as
Jupiter. It does not blink like an airplane or twinkle like
a star. It is, in short, unmistakable.
Some
of the most important sites of the American Revolution are
favored with 4th of July flybys:
At
9:40 p.m. EDT on July 4th, the ISS glides almost directly
over Valley Forge, campsite of George Washington's army. Less
than a minute later it passes over Philadelphia, where the
Declaration of Independence was signed, and then New York
City.
Below:
A telescope pointed at the ISS reveals much of the station's
gangly structure. This video of a flyby in June 2006 comes
from amateur astronomer John Locker of Wirral UK. [More]
 In
Boston, where the revolution was instigated, and Lexington,
where the first shots were fired, the ISS does something special.
Instead of passing directly overhead, it dips a little lower,
gliding right by the Moon and Jupiter. The time to
watch is between 9:40 and 9:41 p.m. EDT.
NASA
did not plan these flybys. Chalk it up to good luck and orbital
mechanics.
If
the space shuttle Discovery launches as planned on July 1st,
it will be docked to the ISS on July 4th, boosting the brightness
of the ensemble. If you can't see one spaceship through the
fireworks, maybe you'll be able to see two.
Enjoy
the fireworks—and what lies beyond. Happy 4th of July from
Science@NASA.
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Author: Dr. Tony
Phillips | Production Editor:
Dr. Tony Phillips | Credit: Science@NASA
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