When we look at the stars with just our eyes...

In article ,
"smallg" writes:
Belelgeuse is a red giant and relatively nearby.

Betelgeuse is a supergiant, actually, but indeed nearby.

Measuring angular diameter with interferometry
is not really "resolving."

Astronomers use "resolve" to mean any method that detects finite
angular size. Two-element interferometry (as pioneered by Michelson)
"resolves" stellar disks but doesn't "image" them. "Speckle
interferometry" detects surface features, though one can quibble
whether it's really imaging. Lunar occultations also detect surface
features. Modern multi-element interferometers do even better. And
as someone mentioned, the disk of Betelgeuse has been imaged with
HST; no quibbling possible about that. These studies give quite a
bit of information on limb darkening and starspots.

The general point is correct, though: study of stars other than the
Sun is much hindered by lack of angular resolution, and the VLT
micro-lensing study is very much to be commended.

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Steve Willner Phone 617-495-7123
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