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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Brown-Nassau spherical computer
From: Hanno Ix
Date: 2015 Mar 31, 14:00 -0800
As you know, I personally like those ingenuous sight reduction slide rules for their sheer ingenuity. However, for actual work on the water I probably would prefer arithmetic methods. Reason: devices will fail one way or the other, and clever ones will fail earlier. I know that from 30 yrs of practical engineering. Sad recent example: electronically controlled doors to the flight deck :(
I recently discussed to some extend sight reduction with David Burch / Starpath to sell him on the hav-Doniol - no success; he goes with the assumed location, period. Re: slide-rules he recognized openly their utility but he was concerned about their being special devices, a situation not generally acceptable.
But since you are making your own devices, perhaps taking along two of them is a good solution for you. Inventing and making them has its own attraction - I know!
H
From: Hanno Ix
Date: 2015 Mar 31, 14:00 -0800
Francis,
not only "so far-so good" but real nice!I recently discussed to some extend sight reduction with David Burch / Starpath to sell him on the hav-Doniol - no success; he goes with the assumed location, period. Re: slide-rules he recognized openly their utility but he was concerned about their being special devices, a situation not generally acceptable.
On Tue, Mar 31, 2015 at 9:11 AM, Francis Upchurch <NoReply_Upchurch@fer3.com> wrote:
Just completed my full sized version. See attached. Details of build on request. Used Harri's wonderful graphs based equations in the original papers (thanks Harri). We had to guess the layout of the B/Y side (or dark side) since the only photo of the original in the Smithsonian is of the A/X side. (If any of our US friends happen to visit the SM, I would appreciate a detailed pic of the far side. repeated email requests have remained unanswered.) However, it works ,so I think it is correct.
So far , getting mean of 2-3' errors for Hc compared to calculator. Hc only takes about a minute. Easier and faster than Bygrave or even calculator.
I think it would pass the "Chichester Test".
More to follow, but so far so good.
Francis
Attached File:
(DSC_0027.JPG: Open and save)
Attached File:
(DSC_0031.JPG: Open and save)
Attached File:
(DSC_0037.JPG: Open and save)
