Imagine photographing a road sign while speeding by it in a car. That’s what astronomers overcame Sunday to take the first ultraviolet snapshots of the moon.
Telescopes on the shuttle Endeavour can zoom in on stars at the edge of the known universe with ease, but they struggle to focus on the moon - a mere 250,000 miles away - because it and the shuttle move so quickly around the Earth.
To make things even more difficult, the moon is so bright that it can throw off the telescopes’ alignment system.
Astronomer Randy Gladstone said Earth’s closest celestial neighbor was by far the most difficult target of the planned 15-day shuttle stargazing mission.
But Gladstone, together with other scientists on the ground and the astrophysicists aboard Endeavour, was able to collect 12 ultraviolet images of the waxing moon Sunday.
Gladstone won’t know how the 70-millimeter pictures turn out until after the shuttle and its crew of seven return from their voyage Friday, but he was optimistic.
“All our exposures went off as planned, and we think we’ll really get some good images,” he said.
They would be the first ultraviolet photographs ever taken of the moon. Such pictures can’t be made from Earth because the atmosphere screens ultraviolet light.
Apollo astronauts used spectroscopes to study sunlight reflecting off the moon’s surface more than 20 years ago, but they didn’t take pictures in the invisible far ultraviolet.
The images from this shuttle flight will be used to test a theory that the ultraviolet surface brightness of a celestial object without an atmosphere can reveal how long that object has been exposed to space.
For example, a newer moon crater theoretically should reflect more ultraviolet light than the surrounding area because dirt there was exposed more recently.