Optical telescope

"How did the universe begin?" . . . . [W]ithin a few years the new giant radio telescopes, which enable man to probe far deeper into interstellar space than the biggest optical telescope, will provide some sort of an answer.

Simply by being the largest optical telescope ever placed above Earth's obscuring atmosphere, the Hubble Space Telescope has yielded spectacular images of cosmic grandeur.

An optical telescope based on a liquid mirror with an aperture of 20 to 100 metres located on the Moon would be able to observe objects 100 to 1,000 times fainter than the proposed next generation of space telescopes.