NASA's Hubble Space Telescope has taken the sharpest visible-light picture yet of atmospheric debris from an object that collided with Jupiter on July 19. NASA scientists decided to interrupt the recently refurbished observatory's checkout and calibration to take the image of a new, expanding spot on the giant planet on July 23.

Discovered by Australian amateur astronomer Anthony Wesley, the spot was created when a small comet or asteroid plunged into Jupiter's atmosphere and disintegrated. The only other time such a feature has been seen on Jupiter was 15 years ago after the collision of fragments from comet Shoemaker-Levy 9.

"Because we believe this magnitude of impact is rare, we are very fortunate to see it with Hubble," said Amy Simon-Miller of NASA's Goddard Space Flight Center in Greenbelt, Md. "Details seen in the Hubble view shows a lumpiness to the debris plume caused by turbulence in Jupiter's atmosphere."

The new Hubble images also confirm that a May servicing visit by space shuttle astronauts was a big success.

"This image of the impact on Jupiter is fantastic," said U.S. Sen. Barbara A. Mikulski, D-Md., chairwoman of the Commerce, Justice and Science Appropriations Subcommittee.

"It tells us that our astronauts and the ground crew at the Goddard Space Flight Center successfully repaired the Hubble telescope. I'm so proud of them and I can't wait to see what's next from Hubble."

For the past several days, Earth-based telescopes have been trained on Jupiter. To capture the unfolding drama 360 million miles away, Matt Mountain, director of the Space Telescope Science Institute in Baltimore, gave observation time to a team of astronomers led by Heidi Hammel of the Space Science Institute in Boulder, Colo.

"Hubble's truly exquisite imaging capability has revealed an astonishing wealth of detail in the impact site," Hammel said. "By combining these images with our ground-based data at other wavelengths, our Hubble data will allow a comprehensive understanding of exactly what is happening to the impact debris."

Simon-Miller estimated the diameter of the impacting object was the size of several football fields. The force of the explosion on Jupiter was thousands of times more powerful than the suspected comet or asteroid that exploded over the Siberian Tunguska River Valley in June 1908.

The image was taken with the Wide Field Camera 3. The new camera, installed by the astronauts aboard space shuttle Atlantis in May, is not yet fully calibrated. While it is possible to obtain celestial images, the camera's full power has yet to be seen.

"This is just one example of what Hubble's new, state-of-the-art camera can do, thanks to the STS-125 astronauts and the entire Hubble team," said Ed Weiler, associate administrator of NASA's Science Mission Directorate in Washington. "However, the best is yet to come."