How does the telescope's  "link-up" work?

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Answered by: Dr. Paul Ho
Still  work in progress?
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by "link", we mean to link up with the other telescopes.  

the GLT is part of an array of telescopes which are physically separated by continental scales.  they include telescopes in europe, hawaii, chile, united states, mexico.  the array of telescopes will behave like a single giant telescope of the size as defined by the furthest separated elements (individual telescope). 

the way to think about this, is to imagine a large telescope the size of the earth.  the mirror is broken, and we have only a few pieces.  if the few pieces still retained the original physical configuration of the original mirror, then they are still in "phase", meaning that the light front will reach all the separate elements at precisely the same time.  this in "phase" or "coherence" means the image is not scrambled in such a way that we cannot recover the image.  when we "link" electronically, either directly with wires, or later by digital techniques, and correct for all "phase delays", then we can reconstruct the image.  this technique is called "aperture synthesis", as in reconstructing the original mirror.  of course there will be errors because of missing so many of the mirror surface, but we have techniques which can correct for the defects.