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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
HO 211 variant
From: Paul Hirose
Date: 1999 Oct 03, 1:35 PM
From: Paul Hirose
Date: 1999 Oct 03, 1:35 PM
The traditional format for HO 211 sight reduction is cleverly laid out, but also uses quite a bit of space: t 156 54 A 40634 d S 56 44 B 26079 A 7773 R A 66713 B 1029 B 1029 A 66713 K S 121 07 A 6744 L S 53 30 K-L 67 37 B 41930 hc 21 50 A 42959 B 3233 Z W 13 A 63480 I've developed a slight variation by shifting the last two columns to the left to use that empty space: t 156 54 A 40634 d S 56 44 B 26079 A 7773 R A 66713 B 1029 K S 121 07 A 6744 L S 53 30 1029 K-L 67 37 B 41930 66713 hc 21 50 A 42959 B 3233 Z W 13 A 63480 One column is all additions and the other all subtractions, as before. I don't mark 1029 as B, because that implies it's B of 53 30', which it is not. It's just copied down from the R row. Same for 66713. Advantage for this method is a more compact arrangement. On a plain sheet of 8.5" wide paper I can work out meridian angle on the left, put the above items in the middle, and compute altitude corrections and intercept on the right. It all fits without writing tiny. Obvious disadvantage is that you have A and B of R not in their "correct" locations, opening the door to mistakes. But I must say that although I've botched HO 211 reductions, it's never been for that reason. For real celestial navigation I recommend using a form, but "blank page" sight reduction is a good training exercise. If you're expert with a method, I think you ought to be able do the entire reduction by heart. It sure feels good to have that ability.
