NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Hav-Doniol checker
From: Andrés Ruiz
Date: 2015 Jun 18, 20:13 +0200
From: Andrés Ruiz
Date: 2015 Jun 18, 20:13 +0200
With this fantastic longhand SR method there are to approaches for Hc and Zn:
I prefer a mixed method for SR:
- by computation
- by Hanno's azimuth diagram
I prefer a mixed method for SR:
- Hc by Hannos's haversine formula,
- and Zn by Hanno's Zn(dec, t, Hc) diagram
As I said, first works fine for all cases, but the diagram has its limitations. Why?, because is based on the sin t * cos dec = sin Z * cos Hc equation.Z calculated in such a way is cuadrantal; 0 <= Z <= 90º, is E/W as the meridian angle is. The other limitation is that 0 <= LHA <= 360º or -180º <= t <= 180º and the diagram has values for t between 0 and 90º.
Of course if you take the approximate Z of the body while is observed the undetermination is solved.
Give me a little time to finish my tutorial and analysis test, and I will send to NavList the results, with my proposal.
best regards.
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