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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The moons of Jupiter for Time or Position?
From: UNK
Date: 2016 May 9, 07:29 -0700
From: UNK
Date: 2016 May 9, 07:29 -0700
Frank said:
> Tables and charts of the motions of the Galilean moons of Jupiter were included in the
> Nautical Almanac & Astronomical Ephemeris from the very beginning, starting in 1767,
>and they were published in other resources long before that.
I was taken aback when I first read this, since one would need a pretty good estimate of the speed of light in order to correct for the relative positions of Earth and Jupiter in their orbits. To my surprise I find that as early as 1728 James Bradley had determined a value that was off by less than one part in 20. See: http://www.speed-light.info/measure/speed_of_light_history.htm
