The more optically think the atmosphere, the dimmer stars get. If one star is a magnitude brigher than a second star, it is a factor of 2.512 times brighter. Astronomers measure how bright a star is, and a star seen though less atmosphere (straight up) is brighter than a star seen through a lot of atmosphere (near the horizion). We measure the "extinction" caused by the atmosphere, and mostly it is about 0.1 mag or so. Cruddy weather has extinctions about .3 mag. Five magnitudes is a factor of 100 in brightness lost, 10 magnitudes is a factor 10,000 (100 squared) punching 14 mags into my calculator means stars would be a factor of 398,107.17 times fainter.
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Date: 2003-05-16 07:27 am (UTC)Astronomers measure how bright a star is, and a star seen though less atmosphere (straight up) is brighter than a star seen through a lot of atmosphere (near the horizion). We measure the "extinction" caused by the atmosphere, and mostly it is about 0.1 mag or so.
Cruddy weather has extinctions about .3 mag.
Five magnitudes is a factor of 100 in brightness lost, 10 magnitudes is a factor 10,000 (100 squared) punching 14 mags into my calculator means stars would be a factor of 398,107.17 times fainter.