The Greek astronomer Hipparchus devised the magnitude system around 150 B.C. Curiously, the larger the magnitude the dimmer the star. It is a logarithmic system: a change of 5 magnitudes corresponds to a factor of 100 in brightness. The sun has a magnitude of -26.7, the moon -12.6. The star Vega is the standard of the industry and has a magnitude of 0. The faintest star you can see with your eye is about +6.5
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LeeH
(published on 05/16/2013)
