Space Station Science Picture of the Day: Asteroid Vesta

Asteroid Vesta

Credit: Don Pettit, ISS Expedition
6 Science Officer, NASA

Explanation: Picture this: You’re at home in your
living room. It’s dark outside. A few of the brightest stars
shine in through the window. Meanwhile, two hundred million kilometers
away, a nearly invisible asteroid glides through space. You grab
your camera, point, click, and capture the space rock on film–right
through your living room window. No problem?

It wasn’t for International Space
Station Science Officer Don
Pettit, who enjoys space-dark
skies and the clearest living room window in the solar system.
On March 24th he pointed his digital camera out the station’s
Destiny
Lab window and snapped this picture of asteroid
Vesta in the constellation Virgo. Vesta
is so big–about 500 km wide–that astronomers consider it to
be a minor
planet. Even so, distant Vesta is barely visible
to the naked eye from the darkest and clearest observing
sites on Earth. Taking its picture through any window is remarkable.

The brightest star in Pettit’s
photo is epsilon Viriginis. Also known as Vindemiatrix,
this star is 60 times more luminous than the Sun and lies 100
light years away. The faintest stars in the photo are approximately
16 times fainter than you can see with your naked eye–i.e.,
the limiting
magnitude was 9. In a larger
version of this image you might also notice some dim smudges.
These are galaxies in the Virgo
Cluster about 50 million light years away. "The
space station functions very well as a platform for astrophotography,"
notes Pettit.