* Astronomy

Don’t miss the spectacular binary star event of the century: the now-imminent periastron passage of Gamma Virginis .
Gamma Virginis was named Porrima by the Romans, after two different goddesses of prophecy in antiquity.



Gamma Virginis is a splendid binary for medium sized telescopes, with an orbit of 168.7 years; positioned about fourteen degrees northwest of the bright star Spica.


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For over 160 of its 169-year period this pair of identical 3rd magnitude stars have been easily resolved at moderate power in a small telescope but, thanks to its extreme orbital eccentricity (about 0.9), Gamma closes for 2 or 3 months around minimum to no more than 1/3 arc second, (a dramatic climax last seen in the winter of 1835-6 by John Herschel, W.R.Dawes and Admiral Smyth.)




The visual appearance of the pair is obvious at the eyepiece over an astonishingly short time -- we are about to witness the only instance in the entire sky visible from northern latitudes of a bright pair visibly and obviously moving, as seen in a 6-inch telescope (minimum), within a 2-year period.

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-- Edited by Blobrana at 07:42, 2005-05-19