Question

What are the difficulties in using ground based optical telescopes? How are they overcome?

Answer 1

The difficulties faced in using ground-based telescopes due to which it does not make good quality observations are:

Intensity of light rays reaching the Earth's surface decreases as some of the light is absorbed by the atmosphere.

The change in atmospheric pressure and temperature cause the light rays to change their path slightly and thus shake the position of the image.

We cannot use optical telescopes during day time because of the presence of sunlight.

Even in night, city lights and cloudy weather can cause hindrance in observing the heavenly bodies.

To overcome the above problems, telescopes are now being erected in space itself. Some of the telescopes in space are:

Hubble telescope: It is an optical telescope launched by the National Aeronautics and Space Administration in $1990$. It is orbiting the Earth at a height of $589$km from it and has a mirror of diameter $94$ inches.

Chandra: It is an X-ray telescope launched by the National Aeronautics and Space Administration in $1999$. Special mirrors that can reflect X-rays are used in this telescope.