spherograph

from The Century Dictionary.

• noun A nautical instrument consisting of a stereographic projection of the sphere upon a disk of pasteboard, in which the meridians and parallels of latitude are laid down to single degrees.

from the GNU version of the Collaborative International Dictionary of English.

• noun An instrument for facilitating the practical use of spherics in navigation and astronomy, being constructed of two cardboards containing various circles, and turning upon each other in such a manner that any possible spherical triangle may be readily found, and the measures of the parts read off by inspection.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An instrument for facilitating the practical use of spherics in navigation and astronomy, constructed of two cardboards containing various circles, turning upon each other in such a manner that any possible spherical triangle may be readily found, and the measures of the parts read off.