Liquid Telescopes on Luna

Desolate, airless and with no people around for hundreds of thousands of kilometers (miles), the Moon is a great place -- for astronomers, that is.

Skywatchers have an enduring hope of one day building a lunar observatory, where gleamings from the earliest stars can be snared without the curse of man-made light pollution and Earth's atmospheric distortion.
But making telescopic mirrors -- dozens are needed in a giant complex -- is eye-wateringly expensive, for it requires grinding and polishing glass to an accuracy of a few tens of billionths of a metre. And, after making a mirror, there's the risk of breaking it when you haul it to the Moon.

Enter an idea that has been kicked around for more than a century and a half -- the liquid mirror telescope.

http://www.spacedaily.com/reports/Mirror_Mirror_On_The_Moon_The_Most_Powerful_Telescope_Of_All_999.html