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Diffusion - Cultural similarities between Old and New Worlds - Atlantis ?

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Author Topic: Diffusion - Cultural similarities between Old and New Worlds - Atlantis ?  (Read 7529 times)
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« Reply #165 on: January 11, 2009, 06:18:57 pm »

57 important stars

In addition, there is a standard roster of 57 stars used by aviators and navigators worldwide and chosen for their ease of identification and wide spacing. A navigator would try to measure the altitude of one of these stars above the horizon during twilight, when both the star and horizon are visible. This yields a "circle of position" on the Earth's globe; the observer must be somewhere on this circle to see the star at a certain altitude at a given time. Other stars yield other circles of position. The point where they all intersect is the observer's location.

In order to be visible against a twilight sky, the majority of the 57 navigation stars are second magnitude or brighter, although a few third magnitude stars were included on the list simply because they occupied regions where none brighter existed (the lower the figure of magnitude, the brighter the star).

Lastly, it was agreed that all these stars should have proper names. But some stars in the far-southern sky lacked such monikers, so after World War II names such as Acrux, Gacrux and Atria appeared on navigators' charts � contractions of the original Greek designations for these stars.

Lastly (and not to sound like Maxwell Smart): Would you believe this official list omits what many might consider to be the most important navigational star in the sky? Yes, it's none other than Polaris, the North Star!

Why? Merely because it lies practically on the celestial pole, so its altitude above the northern horizon alone pretty much indicates the observer's latitude, so there is no need to utilize it for the "circle of position" method described above.

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Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York. 
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