By combining the observational power of six 5-inch aperture telescopes spread over hundreds of feet, the NPOI is able to measure the size of stars down to one milliarcsecond on the sky.

FORBES: Move up http://i.forbesimg.com t Move down

Future aperture upper limits on balloon-borne telescopes are expected to be some 2.5-meters, about the size of the Hubble Space Telescope.

FORBES: Budgets Nudge NASA Toward Balloon-Based Planetary Science: First Target? Comet ISON