Keplern.
/ˈkɛplə/, U.S. /ˈkɛplər/ Used, chiefly in the possessive, to designate things and concepts discovered or investigated by Kepler. Kepler's equation n. the equation θ = ϕ − e sin ϕ relating the mean anomaly θ of a planet to the eccentric anomaly ϕ and the eccentricity e of the orbit. Kepler's laws n. (see law n.1 17c(a)). Kepler's nova n. (or Kepler's star) a supernova which appeared in 1604 in the constellation Ophiuchus and disappeared in 1606. Kepler problem n. (also Kepler's problem) the problem of solving Kepler's equation for the eccentric anomaly of a planet in a known orbit given the mean anomaly, which is effectively that of finding the position of the planet at any given time.
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1714 Philos. Trans. 1713 (Royal Soc.) 28 1 (heading) Problematis Kepleriani, de inveniendo vero motu planetarum, areas tempori proportionales in orbibus ellipticis circa focorum alterum describentium, solutio Newtoniana.]
1721 J. Keill Introd. True Astron. xxiii. 287 (heading) Kepler's problem.
1883 Encycl. Brit. XV. 709/1 By far the most important problem is to find the values of θ and r as functions of t, so that the direction and length of a planet's radius-vector may be determined for any given time. This generally goes by the name of Kepler's Problem.
1890 A. M. Clerke Syst. Stars vii. 97, 1604 Kepler's star.
1902 F. R. Moulton Introd. Celestial Mech. v. 148 (heading) Geometrical derivation of Kepler's equation.
1954 C. Payne-Gaposchkin Introd. Astron. (1956) xiv. 392 Attempts to identify the remains of Tycho's and Kepler's novae with stars have failed.
1958 E. U. Condon & H. Odishaw Handbk. Physics ii. iv. 32/2 Kepler's equation defines ϕ as a function of nt.., which functional relation is the subject of a large mathematical literature.
1964 Yearbook Astron. 1965 49 The most brilliant ‘new star’ of which we have an accurate record was Tycho's Star of 1572, which was, of course, a supernova, and which became equal to Venus... Its only subsequent rival has been Kepler's Star of 1604, which also seems to have been a supernova.
1970 G. K. Woodgate Elem. Atomic Struct. ii. 28 This is called an accidental degeneracy. It occurs likewise in the equivalent classical problem—the Kepler problem of planetary motion under an inverse square law of force.
This entry has not yet been fully updated (first published 1976; most recently modified version published online March 2022).
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n.1721