It can even resolve the surface features on red supergiant stars, which bloat to the diameter of Earth's orbit. Other techniques are limited by the turbulent glare from the stars, which is effectively removed by the use of fibers in FIRST.
In the December issue of the journal Astronomy and Astrophysics, University of California, Berkeley report that they were able to resolve in visible light the two stars in the binary star system Capella, which orbit one another at about the distance of Venus from the sun and until now have been indistinguishable from Earth with the help of FIRST.
