Context: Astronomers are looking forward to opening a new window on the universe by posting high-resolution telescopes on the moon, and in orbit around it.  One such proposal, PRATUSH, hails from India.

Challenges for Earth-based Telescopes:

• Earth-based telescopes, optical telescopes (which collect visible light at longer wavelengths) and radio telescopes (which collect radio waves with the shortest wavelengths), face hurdles due to the atmosphere's interference.

• Optical telescopes struggle with pollution, while radio telescopes contend with electromagnetic interference from various sources, including communication signals.

• It also does not help that the earth’s ionosphere blocks radio waves coming from outer space.

Benefits of placing telescope on Moon

• Scientists are considering placing optical and radio telescopes on the far side of the moon, which always faces away from the earth.

• Clear visibility: The pristine, airless desolation of the moon provides optical telescopes crystal-clear seeing conditions throughout the long lunar night.

• Protection: Radio telescopes on the lunar far side will also be protected by the moon (its diameter is 3,476 km) — that blots out radio transmissions from the earth and electrically charged plasma winds blowing from the Sun.

• It promises the most radio-quiet location in the solar system.

About PRATUSH

• PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen) is being built by the Raman Research Institute (RRI) in Bengaluru with active collaboration from the Indian Space Research Organisation (ISRO).

• Initially, ISRO will place PRATUSH into orbit around the earth. After some fine-tuning, the space agency will launch it moonwards.