NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg B
Date: 2013 Dec 24, 11:36 -0500
Sure thing -let the holidays die down a little and I will post a few more pictures for you. BTW - no micrometer - just a tangent screw, I think they call it;
all fractional readings are done from the vernier. I made it to be functional and accurate - the scale & vernier were done in auto-cad. ultimately a little
frustrating since I have since found that when doing a demo the general public just want the 'readers digest version' of the revolution, and just the cliff's notes
for celestial :-) ) But it was worth making it - right after I finished it I brought it to our local whaling museum and asked the curator what he thought - he said:
"pretty good - I'll be right back" - he came back a few minutes later with a couple of pairs of cotton gloves like restorers use and two complete octant's in mint
condition from 1755 & 1790 from the museums vault! I was overwhelmed! I got to hold what most people only get to stare at from behind a glass cabinet.
These instruments had crossed the Atlantic and other oceans many times - just holding it was like someone had dropped me onto the Bounty or something.
My reproduction is far from perfect I took quite a few liberties as I'm not the worlds best wood worker, but I nailed the size, function, accuracy, and general
appearance - ( using what we call the 10 foot rule....looks good from 10 feet away) My biggest challenge was relearning the math for demos. When I was in
junior high and high school trig tables, log tables, etc. were the norm - we weren't even allowed to use a slide rule until our senior year in high school - the
teachers wanted to make sure we understood all the 'mechanics' of the math.
Happy Holidays Norm,
~Greg
P.S. What group do you do your talks with?
On 12/24/2013 02:39 AM, Norm Goldblatt wrote:
Love it, Greg. Could you post some other views so that we can see the mirror adjustments, bubble mounting and micrometer. This model was obviously made with care and love. You even include a vernier. Good on ya.
Attached is my own 'theatrical' sextant that I use when describing celestial navigation on stage to civilians. It's funny, but actually serves well to illustrate just WHAT angle we're measuring. By pointing it at a overhead stage light, then marching across the stage and taking another sighting, the audience can imagine that the angles are related to my position on the stage.
Norm
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