Satellite Telescopes
The launch of RXTE
Credit: NASA
Because of these problems, some telescopes need to be above the atmosphere, so they have to be put onto satellites and launched into orbit.
Probably the most famous satellite telescope is the Hubble Space Telescope (HST). This avoids the "blurring" of images by the atmosphere and so gets very high-resolution pictures.
Many other satellite telescopes are designed to look at kinds of light, such as X-rays or infra-red light, that do not get through the atmosphere at all.
These satellites have helped astronomers to get a much better understanding of the way in which the Universe works, particularly the physics of very energetic objects such as quasars.
Some astronomical satellites are designed to look back at Earth rather than out into space. These detect changes in weather patterns, temperatures, vegetation and iceflows. They are normally placed in Geostationary Orbits at 35,786 kilometres above the Earth's equator. At this distance they orbit once every 24 hours, so that they remain above the same point on the surface.
