GB150125A - Improvements in or relating to the determination of latitude and longitude by observation of the stars - Google Patents

Abstract

150,125. Wells, T. R. June 23, 1919. Latitude and longitude instruments.-An instrument for determining latitude and longitude by simultaneous observation of two or more stars comprises a base a carrying standards a<1> integral with a fixed ring b within which is rotatably mounted a ring c carrying a bar d, or two stub-axles, on which are pivoted two arms g. Secured to the ring c is a ring e, within which is rotatably mounted a ring f around which the arms g move and to which they can be secured by clamps g<5>, Each arm g has a projection or carrying plate g<2> on which is pivoted a plate g<3> carrying a telescope h. The telescopes are provided with reflectors i to direct the light into the observer's eye. The various rings, and the plates g<2> are suitably graduated. To use the instrument, the base is levelled, the telescopes are set to the colatitudes of two selected stars and the arms g are set so that the angle between them is equal to the difference between the right ascensions of the stars. The whole instrument is then moved until the two stars are seen simultaneously, the latitude then being equal to the inclination of the bar d to the horizontal, and the longitude being obtained from the positions of the arms g relative to the plane of the ring b. A third bar g with telescope &c. may be added.