NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Zenith Fixes
From: Andrés Ruiz
Date: 2019 Mar 26, 10:02 +0100
From: Andrés Ruiz
Date: 2019 Mar 26, 10:02 +0100
Dave,
about the subject "Zenith Fixes",
yes you could call it:
"fix close enough to the body’s zenith",
"fix by sights of stars near its zenith",
"Fix by High altitude observations".
The Fix is obtained in the usual manner.
Move each observation to a common instant of time.
That time for fix is usually the time of the latest sight.
But with with high speed, it could be better to advance them to a future time.
It is the same as obtain a fix, and with it calculate your position after some elapsed time steering at COG, SOG
Of course if the error could be great, (steering , waves, refraction, turbulence in the air, etc) do not advance the fix too much.
DR/AP/EP serves only as an initial position for the calculation, for nothing more.
err = The distance between the assumed position and the improved estimated position in nautical miles
Celestial Fix - n LoPs - by Least squares Sight Reduction algorithm. Paper & Excel
File:
File:
