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I have long wondered how easy it would be to perform this experiment as an amateur. Powerful lasers are quite cheap now. You could get a telescope (doubling as

by tyho 7y ago

I have long wondered how easy it would be to perform this experiment as an amateur. Powerful lasers are quite cheap now. You could get a telescope (doubling as a beam expander and receiver), and some filters to only allow the laser wavelength to your detector.

DrAwdeOccarim 7y ago
Post this to HN when you do it. I would love to follow suit and play around with the idea.
simonh 7y ago
Actually very difficult. They use a 30in telescope for these observations and the beam becomes extremely attenuated. The laser 'spot' projected on the moon is roughly 7km across. Only a tiny fraction of the light is reflected back as the reflector is only a few feet across, and is similarly attenuated on the return journey. The return beam is 20km across by the time it hits the Earth. Due to the extreme attenuation of the final signal the observation takes several hours using highly sensitive equipment, averaging it out to extract meaningful data.
hazeii 7y ago
There's a pretty thorough discussion on Reddit[0]. [0] https://www.reddit.com/r/askscience/comments/qw30x/can_an_amateur_astronomer_test_the_lunar_laser/ https://www.reddit.com/r/askscience/comments/qw30x/can_an_am...
ninju 7y ago
The did on The Big Bang Theory show so it's got to be possible :-) https://movies.stackexchange.com/questions/24686/is-this-laser-experiment-shown-on-big-bang-theory-possible https://movies.stackexchange.com/questions/24686/is-this-las... YouTube link (for those that like the show): https://www.youtube.com/watch?v=_v52LFgUq-8 https://www.youtube.com/watch?v=_v52LFgUq-8