NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Compass Adjustment - A Cautionary tale
From: Trevor Kenchington
Date: 2005 Jan 31, 19:52 -0400
From: Trevor Kenchington
Date: 2005 Jan 31, 19:52 -0400
Jared wrote: > One assumes the problem of compass tilt and north/south zones would not > apply to the (usually cheap) ball-type compasses where the "card" is > actually a white ball, free to move in any direction, i.e. the inexpensive > ones sold for car dashboards and zipper pulls. I disagree. If the very-cheap compasses sold as novelty items did not have counter-weighting based on some assumed dip angle, they wouldn't point north in Canada and the northern U.S. They would point _down_ -- maybe 15 to 25 degrees off straight down. I doubt that such a compass would enjoy many sales, even as a novelty. > I suppose aviation compasses would come closest to this same solution, in a > better quality compass. Maybe. Or do aircraft simply carry gyros? With abundant power available and the higher cost of the basic vehicle (aircraft vs. boat) making a gyro relatively cheaper, why fuss with a magnetic compass? Trevor Kenchington -- Trevor J. Kenchington PhD Gadus@iStar.ca Gadus Associates, Office(902) 889-9250 R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251 Nova Scotia B0J 2L0, CANADA Home (902) 889-3555 Science Serving the Fisheries http://home.istar.ca/~gadus