Optical telescopes situated on the surface of Earth, does not produce images of good quality of the following reasons:
- 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.
Thus, optical telescopes are located in uninhabited places and on higher altitudes such as on top of mountains to reduce the above problems in appreciable amount.
