"Unbelievably large" telescopes proposed for the Moon

It might sound like cutting edge science, but this idea was first proposed by Sir Isaac Newton hundreds of years ago! The idea is that instead of a solid mirror, a mirror be made of a rotating bowl of liquid- the surface will naturally form a curved parabolic shape needed to focus incoming light. The only disadvantage is that the telescope can only point in one direction- straight up!



It turns out that this design is not so novel, though- The University of British Columbia has a six meter rotating liquid mirror in their Zenith telescope- making it the third largest optical telescope in North America. Six meters is about 18 feet, well over 200 inches- our school telescope has an eight inch mirror!
Furthermore, there is another telescope that only points up- the massive 1000 foot ( 12,000 inch!) Arecibo radio telescope in Puerto Rico, the largest single dish telescope of any kind on the entire planet- the largest in the universe as far as we know! That telescope has technology to allow it to be pointed a little bit- otherwise the rotation of the Earth determines where it is pointed.

Of course, if a lunar telescope were placed near one of the moon's poles, it would get a changing view every 18 years or so. The moon, like the earth, wobbles ("precession"). The moon's wobble is completed about every 19 years. Further, of the telescope were located inside a grater, it could stay in the cool dark all the time; solar panels could be placed on illuminated mountain peaks nearby to produce the electricity needed to run it.

So how big is "unbelievably large"? Well, the first proposed would be a 20 meter ( 60 foot) telescope, much larger than any optical telescope on Earth, but others proposed are up to 100 meters across- larger than the length of a football field!




http://science.nasa.gov/headlines/y2008/09oct_liquidmirror.htm?list65645