re: Ground-based telescopes to observe collision:
[The celestial fireworks, scheduled appropriately enough for July 4, won't be visible to unaided eyes on Earth, but hundreds of amateur and professional astronomers are expected to observe the collision through ground-based telescopes. NASA also plans to train the Hubble Space Telescope, the Spitzer infrared telescope and the Chandra X Ray Observatory on the comet for collaborative studies.]
From: Discovery.com