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Re: Celestial Navigation In The Gps Age: Typos?
From: Bill B
Date: 2017 Sep 1, 00:05 -0400
From: Bill B
Date: 2017 Sep 1, 00:05 -0400
On 8/31/2017 3:33 PM, Stan K wrote: > As far as the sun altitude corrections go, they consist of refraction , > parallax, and semi-diameter. refraction and parallax are essentially > the same for lower and upper limbs, but semi-diameter goes from limb to > center by adding for a lower limb sight, but subtracting for an upper > limb sight. Using some nice round numbers for refraction, parallax, and > semi-diameter, in that order: > Tony Apologies. In an attempt to be simplistic I made a gross errors. Stan is correct, parallax is include in the altitude tables. I stated, "When we calculate the Hc of a body (especially the sun and moon) we are calculating the distance from the horizon to the CENTER of the body." It should read. "When we calculate the Hc of a body (especially the sun and moon) we are calculating the angle from the the CENTER of the body to the center of the earth in the absence of atmosphere."
