This article is from the Astronomy FAQ, by Joseph Lazio (jlazio@patriot.net) with numerous contributions by others.
By Steve Willner <swillner@cfa.harvard.edu>
Obvious candidates are alpha Orionis (Betelgeuse, M1-2 Ia-Iab), alpha
Scorpii (Antares, M1.5 Iab-Ib), and alpha Herculis (Rasalgethi, M5
Ib-II). Spectral types come from the Bright Star Catalog. Although
trigonometric parallaxes are listed in the catalog, they will not be
very accurate for stars this far away. I derive photometric distances
of around 400 light years for the first two and 600 light years for
alpha Her. (Anybody have better sources, or do we have to wait for
Hipparcos?) Anybody want to suggest more?
 
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