Brightness of Stars

Brightness of Stars - Brightness of Stars 1. First widely...

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Brightness of Stars 1. First widely used catalogue of stars by their brightness was the Almagest , by Ptolemy in 140 A.D. 2. Had six magnitudes for stars from the brightest to the faintest. 3. A 1 st magnitude star is the brightest and a 6 th magnitude star is the faintest. (naked eye observations) Apparent Magnitude (m) – how bright a star is to an unaided observer on the Earth. 1. In the 9 th Century astronomers were able to make quantitative measures. 2. It was determined that brightest stars were about 100 times brighter than the faintest. (stars that can be seen with the naked eye). 3. This system is a magnitude scale that: i. Shows a difference of 5 magnitudes. ii. A 1 st magnitude star is brighter than a 6 th magnitude star by a factor of exactly 100 times. iii. Each magnitude is 2.512 brighter than the next. iv. The scale is backwards from what your would think it should be. Example 1 – How much brighter is a 1 st magnitude star than a 3 rd magnitude star. Each magnitude is 2.512 brighter than the next, there is an increase of two
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Brightness of Stars - Brightness of Stars 1. First widely...

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