BALTIMORE -- The Hubble Space Telescope will be watching when the University of Maryland's Deep Impact space probe crashes into a comet July 4, setting off a cosmic firework that may be visible on Earth.

The best view is expected to be had by the Deep Impact probe itself, but officials at the Space Telescope Science Institute, which coordinates Hubble's use, say they are ready for anything.

"We will be here and we'll be working," said Cheryl Gundy, a spokeswoman for the Space Telescope Science Institute.

Hubble was also trained on the collision of comet Shoemaker Levy and Jupiter in 1994 and "had those great results. We're hoping well see something similar," Gundy said.

While the Shoemaker Levy collision was the first collision of two solar system bodies ever observed, if all goes well, the Deep Impact mission will mark the first time a spacecraft has struck a comet.

As Deep Impact nears the end of its six-month journey, the Hubble is also observing the comet to help guide mission officials, Gundy said.

Observations by Hubble and the Spitzer space telescopes in 2004 helped paint a clearer picture of the comet, showing it to be about 8.7 miles by 2.5 miles, or half the size of the island of Manhattan, with a matte black color.

Deep Impact, launched Jan. 12, has two parts, an "impactor" that will be released to collide with Tempel 1, possibly creating a stadium-size gouge, and a fly-by craft with instruments to observe the collision...