An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 8 Search : piece
eyepiece
  چشمی   
cašmi (#)

Fr.: oculaire   

A → lens system, also known as an → ocular, used to → magnify the → image formed by the → objective of a → telescope.

eye; → piece.

Cašmi "ocular," adj. of cašmeye + -i adj. suffix.

Kellner eyepiece
  چشمی ِ کلنر   
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
  چشمیِ اردابینی   
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
  تکه   
tekké (#)

Fr.: pièce, morceau, tache   

1) A portion of an object or of material, produced by cutting, tearing, or breaking the whole.
2) An item forming part of a set.
3) A written, musical, or artistic creation (OxfordDictionaries.com).

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
  تکه‌ای   
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.

piece, + -wise, → clockwise.

piecewise continuous function
  کریای ِ پیوسته‌ی ِ تکه‌ای   
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
  چشمی ِ رمزدن   
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
  زمان‌شمار   
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.

time; → piece.

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."