Why have astronomers placed telescope in spaces?

Answer 1

The atmosphere prevents correct observation due to refraction.Telescopes in space are able to provide accurate details of the space objects.

Answer 2

The Earth's atmosphere distorts light that passes through it. So when looking at other celestial objects, the light from those planets or stars has to pass through a distorting layer of air nearly 100 miles thick. To minimize the distortion, astronomers for the last 150 years has built their telescopes and observatories at the peaks of mountains, to get above the thickest and most turbulent layers of air.

Also, as cities have spread out, city light tends to overwhelm the dim stars that astronomers are trying to see. Building on a mountain peak helps to reduce this problem, but the cities often spread out and encroach on the dark sky areas that astronomers need. Classic examples would be Lick Observatory on Mount Hamilton, overlooking San Jose and the Silicon Valley, and Palomar Observatory on Mount Wilson, near San Diego, CA.

By launching a telescope into space, we get COMPLETELY above the atmosphere, and we no longer have to worry about a city expanding around us.

Finally, terrestrial observatories are pretty much limited to nighttime hours, because sunlight is scattered and creates the "blue sky"; this isn't a problem in space. So we can observe full time. Plus, our telescope is orbiting the Earth but isn't ON the Earth, so in some cases we can observe the same targets for days or weeks at a time.

The downside is that with a terrestrial telescope, if something goes wrong the repairman can get there in a pickup truck the next day. With an orbiting telescope, you need a spaceship to perform any repairs, and since the retirement of the Space Shuttle, we've been unable to do any maintenance on the telescopes. So the Kepler Space Telescope, for example, has been crippled by the failure of two of its gyroscopes. If we could get there, we could replace the gyros, but that isn't possible.