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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ed Popko
Date: 2017 Dec 31, 03:44 -0800
Kermit, Sean, Frank:
In my note to Sean [1], I use my HP calculator program version and input Sean's altitude corrections for moon and Aldebaran rather than mine. Sean used NA published equations to compute them, I used the NA tables to look them up.
After using Sean's altitude correction values [2], I get the same A, B and cleared lunar values as he does but our Q values differed a lot. Both our Q values were very small and seemed not to have affected our final cleared lunar value.
But, why such difference computed Q values? When I comparing Sean's Q equation with my calculator equation, I find that I had used
the ATAN function rather than COTAN as he did. I changed ATAN to COTAN and reran:
Q = .55*ACm^2*(1./TAN(LDpc))*(1.0-A^2)/3438. Where x^2 denotes squared and COTAN is 1./TAN(x)
Our values for A, B, Q and final cleared lunar now agree completely.
I am having a small vacation and do not have access to my notes from Frank's lunars workshop. I'm curous as to why I used ATAN rather than COTAN in my Q equation. But even with ATAN, many other lunars test cases agree very well with results published elsewhere but computed by different methods.
Ed
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[1] fer3.com/arc/m2.aspx/First-MoonStar-Lunar-EdPopko-dec-2017-g41062
[2] fer3.com/arc/m2.aspx/First-MoonStar-Lunar-SeanC-dec-2017-g41056