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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: Alexandre Eremenko
Date: 2012 Apr 4, 13:56 -0400
From: Alexandre Eremenko
Date: 2012 Apr 4, 13:56 -0400
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.