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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David C
Date: 2017 Jan 20, 20:06 -0800
Another path I want to follow is checking Blackburne's calculations for the meridian angle. From the 1943 edition of Bowditch (p169) I suspect that the formula he is using is
sin2 1/2t = cos 1/2 (h+L+p) sin 1/2 (L+p-h)/cosL sinp
A quick check of Norie (1918) does not reveal any sin 2 1/2 t table but they are included in Raper (1906). A footnote in Raper states that the table is identical to the log haversines of Inman's tables. I should have recognised this immediately but my mathematics are somewhat rusty (-;
It seems that I have all the material I need to reduce the sights both by Blackburne's method and by 21st century methods.
I have downloaded a copy of the 1922 NA. My investigation would be complete if I could find the 1902 edition. Does anyone know of a copy online?
