High atop a windswept, extinct volcano on the island of Hawai'i are some of the better, if not the best, astronomical sites on Earth. The Mauna Kea Observatories include 13 telescopes run by eleven different countries, including the world's largest optical/infrared scope, the Keck Observatory.
Hence, it is not surprising that Mauna Kea was factored in to NASA's Deep Impact mission to comet Tempel 1. According to this article, NASA planned the impact of its probe so that telescopes on Mauna Kea would have the best view possible.
Assuming that the July 3rd mission goes as planned, the Hawaii observatories (and their sister observatories on the island of Mau'i) should have the first, and perhaps best views, of the experiment.
