NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2017 Jan 15, 05:24 -0000
Re. Home made Octant.
The book by Tony Crowley “The Lo-Tech Navigator” has a number of easy homemade projects including an Octant he called Henry.
His is easy to make and as John D Howard suggested , uses the simple approach of sticking the scale on the outer rim, so can adapt a linear scale (no bending). (He has one and for the Vernia in the book which can be copied directly)
He claims an accuracy to 1.5’.
Anyway, probably as good as the Davies Mk 3.
Francis
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of David Pike
Sent: 14 January 2017 20:49
To: francisupchurch@gmail.com
Subject: [NavList] Re: When even a Davis Mark 3 is too much
John D Howard you said: With a little skill and time I am sure a handy person could build a sextant to one minute arc.
It is possible. You really need a lathe with a dividing head and a technician to get you started for both the arc and the vernier. I'm afraid I rather rushed the vernier, and 35 years later, I'd need a lathe, another instruction session, and a lot of patience to do it again. It was a kind of "Done it. Got the tee-shirt" sort of a thing. I make the reading 67 degrees 46 or 47 minutes. DaveP
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