Four telescope link-up creates world's largest mirror (BBC)

[eppur_se_muova]

By Katia Moskvitch
Technology reporter, BBC News, Paranal Observatory, Chile

Astronomers have created the world's largest virtual optical telescope linking four telescopes in Chile, so that they operate as a single device.

The telescopes of the Very Large Telescope (VLT) at the Paranal observatory form a virtual mirror of 130 metres in diameter.

A previous attempt to link the telescopes last March failed.

Thursday's link-up was the system's scientific verification - the final step before scientific work starts.

Linking all four units of the VLT will give scientists a much more detailed look at the universe than previous experiments using just two or three telescopes to create a virtual mirror.
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more: http://www.bbc.co.uk/news/science-environment-16869022

[Kablooie]

1. Couldn't this be done with telescopes thousands of miles apart?

As long as they could observe the same location wouldn't it be theoretically possible to make a telescope that was several thousand miles across?
How much more clarity would that bring?

[eppur_se_muova]

2. The light beams have to interact with each other directly ...

I don't understand all the details, but basically they're setting up an interferometer.