Yes, I think closest approach to earth was in early May. The day before impact will be the closest approach to the sun.

Previous observations of Tempel 1 taken with ground-based telescopes indicated the comet is dark and oblong, with a width of a few miles, or kilometers. Spitzer and Hubble refined these measurements, revealing a matte black comet approximately 14 by 4 kilometers (8.7 by 2.5 miles), or roughly one-half the size of Manhattan.

"Spitzer was crucial in pinning down the comet's size," said Dr. Michael A'Hearn of the University of Maryland, College Park. He is principal investigator for Deep Impact and the Hubble observations. "We'll know exactly what it looks like when we get there."