Friday, July 30, 2004

Proper Motion

In astronomy, the apparent motion of a star across the celestial sphere at right angles to the observer's line of sight; any radial motion (toward or away from the Sun) is not included. Proper motion is generally measured in seconds of arc per year; the largest known is that of Barnard's star in the constellation Ophiuchus, about 10� yearly. The English astronomer Edmond

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