07-04-2017, 06:48 AM
(07-03-2017, 08:53 PM)P.Rutherford Wrote: Gentlemen,
Perhaps for a refinement in determining longitude by, say, Sunset, you could use the Altitude Correction Tables- https://thenauticalalmanac.com/Altitude%...0Table.pdf
....using page 2 of the Table.
Also, in each of The Nautical Almanacs on this site CelNav57 put in an explanation of The Nautical Almanac. I think it's on page 7 & 8 of each Almanac
"Sunset- the approximate GMT/UT when the Sun is 0° 50' (semi-diameter plus refraction) below the
horizon. First locate your approximate Latitude in the Lat. column and then follow across horizontally to
the right to find the time."
The problem might be clearly determining exactly when Sunset occurs. "Below the horizon" will probably trick our eyes as refraction is pretty large. "On the hard" will be difficult as a landscape horizon is so variable. Sea horizon is more cooperative.
Nice work Rumata!
Paul (it's too hot to sail today)
But....in difficult straits it might be the only way you could get a clear idea of the time.
Thank you, P. Rutherford.