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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Getting ready for a spring demo...
From: Greg B
Date: 2013 Dec 28, 18:13 -0500
From: Greg B
Date: 2013 Dec 28, 18:13 -0500
Hi All, I'm starting to get ready for a spring talk / demo at a re-enacting event (for re-enactors only. also known as a "pre-1840 event") I'm starting to build reproductions of Lewis & Clark's artificial horizons so far I have built a wind screen to "cover a bowl of water" and am working on a "3 legged wooden 'table' (3" X 4") to hold a spirit level and a 'mirror from a sextant' " I will pass on the 3ed one - a mercury bath. any suggestions? I disguised a modern 99 cent store level to look like a period level and I removed the old level lines and redid them to be sensitive to 1' of arc.my test procedure was to level the level with a high quality machinest level & table. then I placed the level at one end of a 6ft. 2X4, I then raised the far end 1.2 inches according to my calculations: (6ft X 12in) = 72in X Tan 0.01666666 deg = 1.2in and the bubble moved almost entirely out of the marks. Am I correct in assuming I can now resolve 1' of arc? Will this now be the resolution of my sights? suggestions & critiques gratefully accepted. ~Greg P.S. I love to do this type of stuff because this is how I learn it's also been called "experimental archeology".