5 feet long and 14 feet in diameter) and weighs 12 tons. It looks like nothing more than a five-story tower of stacked silver canisters. But each canister houses important telescope equipment. The telescope has focusing mirrors, computers, imaging instruments, and pointing and control mechanisms. Extending from the telescope are solar panels for generating electricity and antennae for communicating with operators on the ground.
Scientists can see better with Hubble than with any telescope on the ground because Hubble travels above the atmosphere. On Earth, the atmosphere makes pictures taken by visible-light telescopes look smeary û clouds, precipitation, and atmospheric temperature changes get in the way. But in the near vacuum of space, Hubble can take very clear, crisp pictures -- no clouds or atmosphere exist between it and the star or galaxy it's observing.
Every day Hubble archives between three and five gigabytes of data and sends 10 to 15 gigabytes to astronomers around the world.
