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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Current Sextant Manufacturers
From: Alexandre Eremenko
Date: 2012 Mar 31, 12:46 -0400
From: Alexandre Eremenko
Date: 2012 Mar 31, 12:46 -0400
Greg, > It is not ridiculous to have the three armed protractor (position > pointer) measuring to 1' moa. > Cartography and chart sounding updates would > require this precision. I am saying that such precision simply cannot be achieved in plotting a dot on a map. Indeed, the arm length of the protractor is about 2 feet. That is 60cm. An arc of 1' of radius 60cm is 0.02cm. Two hundredth of a centimeter. You do not distinguish two dots at such distance, you cannot actually plot with such precision (your pencil point is much larger), and you cannot attach the protractor to the given points on the map with such precision. 1/4 of a degree would be enough, and for this one does not need a 1' vernier. Alex.
