DOUBLE-STAR SEA COLLIMATOR SEXTANT AND PROCEDURE OF SIMULTANEOUS OBSERVATION OF PAIR OF STARS WITH SUPERIMPOSITION OF THEIR IMAGES Russian patent published in 2002 - IPC

FIELD: navigation. SUBSTANCE: double-star sea collimator sextant is used on ships and vessels to determine point of observation of heavenly bodies. It is telescope with illuminated grid of hairs in field of vision of wide-angle eye-piece that has form of mutually perpendicular vertical and horizontal hairs crossing on optical axis. Two beam splitters are placed in front of objective lens to form three optical channels. One channel includes measurement prism with reading unit, second channel has collimator with weight which images grid of hairs in field of vision of eye-piece which accurately superimposes on grid of eyepiece when sighting plane of sextant lies in plane of vertical line of weight. Third channel with angular prism forms image which superimposes exactly on image of first channel when index of reading unit is set at zero. Simultaneous observation of pair of heavenly bodies with superimposition of their images assumes preliminary computation of angular distance between pair of stars selected for observation, setting of computed value in reading unit, observation with reading from new zero point and measurement in turn of arcs and vertical of one star to spherical perpendicular dropped from image of second star. In this case grid of collimator hairs is kept precisely superimposed on grid of hairs of eye-piece or grid of hairs of eye-piece is kept in the middle between extreme positions of collimator grid and mean moment of universal time of measurement is recorded by chronometer. Then latitude and longitude of position is computed by known and measured values. EFFECT: simplified observation procedure, increased timeliness and precision of determination of position. 2 cl, 3 dwg