How big is the Spitzer Space Telescope?
Astronomers typically characterize the size of a telescope by the diameter of its primary mirror. The Spitzer Space Telescope mirror is 0.85 meters in diameter. While this may seem small compared to telescopes on Earth (some of which reach 8-10 meters in diameter), Spitzer will be in space and hence will not suffer from the atmospheric distortion. In general, a smaller telescope in space can replicate the capabilities of a larger telescope on Earth. Despite its modest size, Spitzer is the largest infrared telescope ever put into space. The entire Observatory has a mass of about 935 kilograms, or about 2000 pounds.
