NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Andrés Ruiz
Date: 2010 Mar 10, 16:49 +0100
I think the nomenclature
is something confused in this issue! Only for clarify:
The method is the same
as in Lunars doing SD = 0 and Parallax = 0
Sextant altitudes: Hs1,
Hs2
Apparent altitudes: m, s
Observed or true: M, S
Star 1:
m = Hs1
- Dip
M = Hs1
- Dip - R1
Star 2:
s = Hs2
- Dip
S = Hs2
- Dip - R2,
Apparent distance:
d ->
sextant
Correction for
refraction:
Do = YoungFormula( double m, double M, double s, double S, double d )
{
double a1 = COS( d );
double a2 = COS( m+s );
double a3 =
(COS(M)*COS(S))/(COS(m)*COS(s));
double a4 = COS( M+S );
return( ACOS( (a1+a2)*a3-a4 ) );
}
Calculated star-star
distance:
cos D = sin dec1 sin dec2 +
cos dec1 cos dec2 cos (SHA1-SHA2)
cos D = sin dec1 sin dec2 +
cos dec1 cos dec2 cos (GHA1-GHA2)
Error = IE + arcError = D – Do
regards,
---
Andrés Ruiz
Navigational Algorithms
https://sites.google.com/site/navigationalalgorithms/