Asteroid Juno Grabs the Spotlight
Toward the end of September, the sun will turn a spotlight on the
asteroid Juno, giving that bulky lump of rock a rare featured cameo in
the night sky. Those who get out to a dark, unpolluted sky will be able
to spot the asteroid's silvery glint near the planet Uranus with a pair
of binoculars.
"It can usually be seen by a good amateur telescope, but the
guy on the street doesn't usually get a chance to observe it," said Don
Yeomans, manager of NASA's Near Earth Object Program Office at JPL.
"This is going to be as bright as it gets until 2018."
Juno, one of the first asteroids discovered, is thought to be
the parent of many of the meteorites that rain on Earth. The asteroid
is composed mostly of hardy silicate rock, which is tough enough that
fragments broken off by collisions can often survive a trip through
Earth's atmosphere.
Though pockmarked by bang-ups with other asteroids, Juno is large; in
fact, it is the tenth largest asteroid. It measures about 234
kilometers (145 miles) in diameter, or about one-fifteenth the diameter
of the moon.
The asteroid, which orbits the sun on a track between Mars and
Jupiter, will be at its brightest on Sept. 21, when it is zooming
around the sun at about 22 kilometers per second (49,000 miles per
hour). At that time, its apparent magnitude will be 7.6, which is about
two-and- a-half times brighter than normal. The extra brightness will
come from its position in a direct line with the sun and its proximity
to Earth. (The asteroid will still be about 180 million kilometers [112
million miles] away, so there is no danger it will fall towards Earth.)
Skywatchers with telescopes can probably see Juno from now
until the end of the year, but it is most visible to binoculars in late
September. On or before Sept. 21, look for Juno near midnight a few
degrees east of the brighter glow of Uranus and in the constellation
Pisces. It will look like a gray dot in the sky, and each night at the
end of September, it will appear slightly more southwest of its
location the night before. By Sept. 25, it will be closer to the
constellation Aquarius and best seen before midnight.
Posted at 03:19 am by
dolablog