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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Station pointer London UK
From: Ken Gebhart
Date: 2012 Apr 4, 15:29 -0500
From: Ken Gebhart
Date: 2012 Apr 4, 15:29 -0500
Alex, Yes it is made by the same factory, and possibly is a copy of the Russian model. Your comment is certainly correct, and we are replacing "determine the direction" with "identifies". As for the two solutions, we didn't want to confuse the reader, or start a new dialog about the math. Thanks for your comments. Ken On Apr 4, 2012, at 12:56 PM, Alexandre E Eremenko wrote: > > Indeed! > > I am surprized. They do not say who makes them, > Ken, is it by the Astra factory? > The construction seems exactly the same as of the Soviet one > that I have, except that the Soviet one is made entirely of bronze, > and this one of an aluminium alloy. > The box is of slightly different construction. > (Soviet ones on e-bay usually cost a bit less). > > There are several imprecise points in the Celestaire description. > > a) You do not need to measure the DIRECTIONS (bearings) of 3 objects > but only TWO HORIZONTAL ANGLES between them. This is done with > a sextant. (A direction is measured with a compass, and it is > hard, if not at all impossibe to measure with 1' accuracy). > > b) "There is only one solution". There are generally 2 solutions. > The are usually far apart, if one takes the right objects to > measure angles between them, and one of the solutions is usually on > land. > Geometrically, these solutions are the points of intersection > of two circles (position lines). Two circles usually intersect at 2 > points. > > Alex. > > >