.title
Why the Hubble Space Telescope?

.synonyms
Introduction article

.description
A short description of the telescope and its purpose.

.contents

.para
     Imagine trying to see the clouds from the bottom of a muddy pond.
That is how astronomers describe their view of the stars and planets
through the Earth's atmosphere.  As advanced as astronomical technology
has become, our capabilities will be forever limited by the turbulence
and brightness of our atmosphere.  Even the finest ground observatories,
such as the one at Mt. Palomar, California, are restricted by these
conditions.  In addition, the selective absorption of the atmosphere,
which lets in visible light and radio waves emitted by stars
and planets, but excludes most other forms of energy, limits our
knowledge of celestial bodies.


.para
     To open the universe to observation in infrared, ultraviolet,
x-ray, gamma-ray, and cosmic ray energies, NASA launched numerous
satellites, each helping to explain different processes behind
astronomical phenomena.  But, to date, the value of these orbiting
observatories has been limited by their relatively small size and
limited spectral capability.


.para
     Now, for the first time, a ground-sized observatory will be placed
in orbit to view the universe in visible and ultraviolet light unobscured
by Earth's atmosphere.


.para
     Called the .~ Edwin P. Hubble Space Telescope~, the new observatory is
a NASA-wide and international .~ cooperative effort~.  Its name honors
Edwin P. Hubble (1889-1953), who discovered that the universe extends
far beyond the Milky Way galaxy.


.para
     The .~ Hubble Space Telescope~ will weigh about 25,000 pounds (11,300
kg) and will have a length of 43 feet (13.1 m) and a diameter of 14 feet 
(4.26 m).  Its major components are an .~ optical telescope assembly~,
five .~ scientific instruments~, and a .~ support systems module~.