Radio-telescopes (e.g. the Very Large Array (VLA)) can simulate one gigantic dish by using separate smaller dishes.

Q: Could such an array of optical telescopes potentially see an exoplanet at say 20 LY away?


  • The array is space-based, at an ideal location such as the Earth-Sun L2 Lagrangian Point
  • Assume the exoplanet of interest is defined as a rockey planet up to 5 times the diameter of earth
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    $\begingroup$ I think that "Can anyone speculate how [...]" violates the FAQs ban on discussion. One might consider asking for a list of current proposals, but that would be Not Constructive (tm). I think that there are good, specific questions along these lines, but you will have to be more specific. Your (2), for instance is fine on it's own, and something like "Are there any plans for a space based multi-antenna interferometer in the radio band (i.e. VLA in space)?" would also be fine. I'm going to close for the moment, but please edit and flag to get it re-opened. There is a good question in here. $\endgroup$ Oct 25 '12 at 19:04
  • $\begingroup$ Question 2 quite relies on question 1. In fact I don't see why there needs to be 2 questions, just ask the second. $\endgroup$
    – Jonathan.
    Jan 10 '13 at 20:14
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    $\begingroup$ @Lakey, radio telescopes use a very different way of collecting and combining their data than we would with an optical telescope. It relies on catching the same photon/wavefront in multiple detectors so we can combine them together. Optically, things work very differently. Take a look at Optical Interferometry if you're interested. $\endgroup$
    – Carl
    May 23 '13 at 21:05

Sure...why not? The answer is really in the diffraction limit.

Two NASA missions planned to address this based upon sparse apertures: SIM and TPF. SIM (http://en.wikipedia.org/wiki/Space_Interferometry_Mission) was a variable distance pair of telescopes. TPF (http://exep.jpl.nasa.gov/TPF-I/tpf-I_index.cfm) was a synchronized flying mission of several telescopes phased together.

Concepts today are based upon Fourier Telescopy (several apertures phased together sort of like an interferometer or a star nulling telescope). The Navy does something similar on the ground (see: NPOI http://www.lowell.edu/research_telescopes_npoi.php). JPL / Caltech have done something similar on the ground at Palomar Observatory (http://www.astro.caltech.edu/palomar/pti.html)


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