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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.
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