ANALEMMA

ANALEMMA, a Planisphere; or Projection of the Sphere, on the Plane of the Meridian, orthographically made, by straight Lines and Ellipses; the Eye being supposed to be at an infinite Distance; and in the East or West Points of the Horizon. See PLANISPHERE, PROJECTION, and SPHERE. The Analemma is also used for an Astrolabe; or kind of Instrument, consisting of the Furniture of the same Projection, drawn on a Plate of Brass or Wood; with a Horizon or Cursor fitted to it. See ASTROLABE. Its use is for finding the Time of the Sun’s rising and setting, the Length of the longest Day in any Latitude, and the Hour of the Day. The Analemma is also of considerable use among Dialists, for laying down the Signs of the Zodiac, with the Length of Days, and other Matters of Furniture, upon Dials, etc. See DIAL, and FURNITURE. The Word is derived from the Greek ἀνάλημμα (analemma), of ἀναλαμβάνω (analambano), I resume.

ANALEMMA