Apparatus for mechanically solving spherical trigonometrical problems

摘要

212,247. Monney, C., R. March 3, 1923, [Convention date]. Spherical-trigonometry calculators.-In an instrument for determining latitude, azimuth &c. comprising two pairs of arcs for representing the co-ordinates of a star in the altazimuth and equatorial systems and bearing cursors connected together to represent the star's position, the base 2 (the meridional plane) supports rigidly an arc 1 representing the visible horizon and pivotally an arc 3 representing the star's vertical circle. Rotatably mounted at 7 is a spider the long arms 7b of which may be set to represent the polar axis and for this purpose carry a vernier 11 cooperating with a scale 10. The spider supports two arcs 6, 9 at right angles corresponding with the celestial equator and the hour circle respectively, and the arcs 3, 9 are provided with cursors 5a, 5b connected by a pivot 12.