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‖ analemma|ænəˈlɛmə|
[L. analemma the pedestal of a sun-dial, hence the sun-dial itself, a. Gr. ἀνάληµµα a prop or support, f. ἀναλαµβ-άν-ειν to take up, resume, repair.]
†1. orig. A sort of sun-dial. Obs. (and perh. never in Eng.)
1753Chambers Cycl. Supp., Analemma in ancient writers denotes those sort of sun-dials which shew only the height of the sun at noon, every day, by the largeness of the shadow of the gnomon.
2. An orthographical projection of the sphere made on the plane of the meridian, the eye being supposed to be at an infinite distance and in the east or west point of the horizon; used in dialling, etc.
1652R. Austin in Rigaud Corr. Sci. Men (1841) I. 74 The triangles, either in your Analemma or perspective, which serve for the last propositions in your astronomical operations. 1693E. Halley in Phil. Trans. XVII. 881 Fig. 10..is the Analemma projected on the Plain of the Meridian.
3. A gnomon or astrolabe, having the projection of the sphere on a plate of wood or brass, with a horizon or cursor fitted to it, formerly used in solving certain astronomical problems.
1667Phil. Trans. II. 436 A good Globe or Planisphere..that is, the Analemma, contrived into a form of Instrument for the use of the publick. 1685J. Twisden (title) Use of the great Planisphere called the Analemma in the resolution of some useful Problems of Astronomy. 1796Hutton Math. Dict. I. 106 The oldest treatise we have on the analemma, was written by Ptolemy.
4. A scale of the sun's daily declination drawn from tropic to tropic on artificial terrestrial globes.
The Analemma is drawn either as a double line, a long ellipse, or as an elongated 8 crossing the equator, and is placed in the Pacific Ocean where it least interferes with geographical features.
1832Terrestrial Globe by Mardins, has The Analemma.
1876Chambers Astron. 910 Analemma, a scale painted on globes, and having reference to the motion of the sun. |