eyepiece cašmi (#) Fr.: oculaire A → lens system, also known as an → ocular, used to → magnify the → image formed by the → objective of a → telescope. Cašmi "ocular," adj. of cašm→ eye + -i adj. suffix. |
Kellner eyepiece cešmi-ye Kellner (#) Fr.: oculaire de Kellner The first achromatic eyepiece consisting of a convex lens and a plano-convex lens. The convex surfaces are turned toward one another. Named after the inventor Carl Kellner (1826-1855), a German engineer and optician; → eyepiece |
orthoscopic eyepiece cešmi-ye ardâbini Fr.: oculaire orthoscopique A telescopic eyepiece that produces a wide field of view (between 40° and 50°). The eyepiece consists of a single element lens that is normally plano-convex, and a cemented triplet that is usually symmetrical. → orthoscopic; → eyepiece. |
piece tekké (#) Fr.: pièce, morceau, tache 1) A portion of an object or of material, produced by cutting, tearing, or breaking
the whole. M.E. pece, peece, from O.Fr. piece, from V.L. *pettia, probably from Gaulish (cf. Welsh peth "thing;" Breton pez "piece"). Teké "piece, patch." |
piecewise tekke-yi Fr.: par morceaux Denoting a → function that is defined on a sequence of → intervals or pieces. For example: |x| = -x for x < 0, x = 0 for x = 0, and x = x for x > 0. |
piecewise continuous function karyâ-ye peyvaste-ye tekke-yi Fr.: fonction continue par morceaux A function f(x) in an interval if :1) the interval can be divided into a finite number of pieces in each of which f(x) is continuous, and 2) the limits of f(x) as x approaches the boundary point of each piece are finite. In other words, a piecewise continuous function is one that is made up of a finite number of continuous pieces. → piecewise; → continuous; → function. |
Ramsden eyepiece cešmi-ye Ramsden (#) Fr.: oculaire de Ramsden An eyepiece consisting of two planoconvex lenses of the same focal length, placed with the convex sides facing each other and with a separation between the lenses of about two-thirds of the focal length of each. Named after Jesse Ramsden (1735-1800), English maker of astronomical instruments; → eyepiece. |
timepiece zamân-šomâr (#) Fr.: appareil horaire Any mechanical, electric, or electronic device, such as a clock or watch, designed to measure and display the passage of time. Zamân-šomâr, literally "time counter," from zamân, → time, + šomâr "counter," from šomârdan "to count," from Mid.Pers. ôšmârtan, ôšmurtan "to reckon, calculate, enumerate, account for," from Av. base (š)mar- "to have in mind, remember, recall," pati-šmar- "to recall; to long for," hišmar-, cf. Skt. smar- "to remember, become aware," smarati "he remembers," L. memor, memoria, Gk. mermera "care," merimna "anxious thought, sorrow," martyr "witness." |