Can two optical telescopes placed hundreds of miles apart be used as a powerful interferometer?

Radio telescopes can be combined into interferometers right round the
Earth because we can record every bump and wiggle of the radio waves
on tape, bring the tapes to one central location, and combine the
waves in an "interferometer inside the computer".

We can't do this with optical telescopes, like you suggested for Keck
and Palomar, because the frequency of light waves is so high (or
another way to say it, the wavelength is so short). In light waves,
the wiggling of the electric and magnetic fields is so abrupt and
quick that with current technology we can't record it in enough
detail. The only way so far that we can build an optical
interferometer, is to combine the two light beams directly. To do
that, the two telescopes have to be no more than a few meters apart,
like the two Keck telescopes, or at most a few hundred meters, like
the mirrors of the SUSI telescope in Narrabri, Australia.

Best wishes,
-Neal.

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