An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1965 Search : ion
annual motion
  جنبش ِ سالانه   
jonbeš-e sâlâné

Fr.: mouvement annuel   

The annual apparent motion of the → Sun in the sky with respect to → fixed stars along the path called → ecliptic. The apparent annual motion is due to the → Earth's → revolution about the Sun. In the course of this motion, the Sun appears to shifts about 1° eastward per day.

annual; → motion.

annual variation
  ورتش ِ سالانه   
varteš-e sâlâné

Fr.: variation annuelle   

Generally, the variation of a quantity over a year. In particular the yearly change in the right ascension or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star.

annual; → variation.

anomalous dispersion
  پاشش ِ ناسان   
pâšeš-e nâsân

Fr.: dispesrion anormale   

The phenomenon whereby the → refractive index of light in a medium changes rapidly with wavelength in the vicinity of an → absorption band. Hence the → dispersion curve of the substance shows marked deviations from → Cauchy's equation, in contrast with the behavior of → normal dispersion. On the shorter λ side of the absorption band the refractive index falls off more rapidly than required by Cauchy's equation representing values of n for visible light. On the long λ side of the absorption band the index is very high, decreasing at first rapidly and then more slowly as one goes beyond the absorption band.

anomalous; → dispersion.

anticorrelation
  پادهم‌باز‌آنش   
pâdhambâzâneš

Fr.: anticorrelation   

Statistics: The correlation coefficient of two random variables X and Y is in general defined as the ratio of the Cov(X,Y) to the two standard deviations of X and Y. It varies between 1 and -1 corresponding to complete correlation or anticorrelation.

Anticorrelation, from → anti- + → correlation.

Pâdhambâzâneš, from pâd-, → anti-, + hambâzâneš, → correlation.

Antoine equation
  هموگش ِ آنتوان   
hamugeš-e Antoine

Fr.: équation d'Antoine   

A mathematical expression, derived from the → Clausius-Clapeyron equation, of the relation between the vapor pressure and the temperature of pure substances. It shows that the logarithm of vapor pressure is linearly dependent on the reciprocal of → absolute temperature.

Named after Louis Charles Antoine (1825-?), a French marine engineer, who derived the equation; → equation.

aphelion
  اپاهور   
apâhur

Fr.: aphélie   

The point in the orbit of a planet, or other object in the solar system, which is furthest from the Sun.

Aphelion, from L. aphelium, from Gk. → apo- + helios "sun," cognate with L. sol, Skt. surya, Av. hvar-, Mod.Pers. xor, hur, O.H.G. sunna, Ger. Sonne, E. sun; PIE *sawel- "sun".

Apâhur, from Pers. prefix apâ, → apo-, + hur "sun."

aphelion distance
  اپست ِ اپاهوری   
apest-e apâhuri

Fr.: distance à l'aphélie   

The distance between the → Sun and an → object in orbit around it when they are at their farthest approach.

perihelion; → distance.

apocynthion
  اپامه، اپاماه   
apâmah, apâmâh

Fr.: apolune   

The point in a lunar orbit that is farthest from the center of the Lune. Also apolune.

Apocynthion, from → apo- "away from, off" + cynthion, from Gk. Cynthia "goddess of the Moon."

Apâmah, apâmâh, from apâ, → apo-, + mah, mâh, → Moon.

apodization
  پازدایی   
pâzodâyi

Fr.: apodisation   

1) Generally, any process suppressing the secondary maxima of a diffraction pattern, such as the faint rings around the Airy disk of an optical image. This allows the telescope to resolve finer details.
2) Over a telescope aperture, the use of a screen that progressively cuts down, from the center to the edge of the aperture, the amount of light transmitted, in order to reduce diffraction.
3) A mathematical treatment carried out on data received from an interferometer before the Fourier transformation is calculated to obtain the spectrum.

Apodization from v. apodize, → a- "negation prefix" + pod from Gk. podos "foot" (compare with Pers. , see below) + -tion "noun forming suffix;" literally "removing feet," i.e. suppressing the secondary maxima at the side of the Airy spot.

Pâzodâyi "removing feet," from "foot," Mid.Pers. pâd, pây , Av. pad-, Skt. pat, Gk. pos, gen. podos, L. pes, gen. pedis, PIE *pod-/*ped-. Zodâyi, n. from zodudan "to polish, clean," Mid.Pers. uzdâtan, Av. uzdâ-, from uz-, → ex-, + dâ- "make, create."

apparent position
  نهش ِ پدیدار، جا‌ی ~   
naheš-e padidâr, jâ-ye ~

Fr.: position apparente   

1) The position on the celestial sphere at which a heavenly body would be seen from the Earth at a particular time.
2) A position given by the coordinates calculated for a star, if it were seen from the Earth's centre, relative to the → real equator and the → real equinox, at a certain date. It includes the displacements from one heliocentric direction, given in a stellar catalogue, due to → precession, → nutation, → aberration, → proper motions, → annual parallax, and light gravitational deviation (M.S.: SDE).

apparent; → position.

apparition
  پدیداری، پدیدارش   
padidâri (#), padidâreš

Fr.: apparition   

A period during which a → planet, → asteroid, or → comet is observable, generally between two successive → conjunctions of the body with the Sun.

M.E. apparicioun, from O.Fr. apparition, from L.L. appritionem "an appearance," from L. apparitus, p.p. of apparere "to appear."

Padidâri, n. from → padidâr + -i; padidâreš, verbal n. from *padidâridan.

apperception
  بر‌آگرتش   
barâgerteš

Fr.: aperception   

In psychology of education, the fundamental process in acquiring knowledge, and the part played by existing knowledge.

From Fr. aperception, from N.L. apperceptionem, from ap- variant of → ad- before p + → perception.

From prefix bar- "on, upon, up" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + âgerteš, → perception.

application
  آتاهش، کاربرد   
âtâheš, kârbord (#)

Fr.: application   

1) General: The act of applying to a particular purpose or use.
2) Computers: A program that performs a specific function for the user, as contrasted with an environment or operating system. Some examples are Microsoft Windows, Microsoft Word, and Adobe Photoshop. The word "application" is used because each program has a specific application for the user.

Verbal noun of → apply.

application software
  نرم‌افزار ِ آتاهشی   
narm-afzâr-e âtâheši

Fr.: logiciel d'application   

A software with a specific function, such as a word processor or game. Contrast with operating system software.

application; → software.

apprehension
  درنوتش   
darnuteš

Fr.: appréhension   

1) Anxiety or fear that something bad or unpleasant will happen.
2) Understanding; grasp.
3) The action of arresting someone (Oxford Dictionary, lexico.com).

Verbal noun of → apprehend.

approximation
  نزدینش   
nazdineš

Fr.: approximation   

1) General: A guess or estimate; nearness in space, position, degree.
2) Math., Physics: Result that is not quite exact, but is within the limits of accuracy required for a given purpose.

Approximation, verbal noun of → approximate.

Nazdineš, verbal noun of nazdinidan, → approximate.

apsidal motion
  جنبش ِ هباکی   
jonbeš-e habâki

Fr.: mouvement apsidial   

Rotation of the → line of apsides in the plane of the orbit in the same direction as the → revolution of the → secondary body. The major axis of the Earth's orbit rotates by 11.6 arcseconds per year.

apsidal; → motion.

apsidal precession
  پیشایانِ هباکی   
pišâyân-e habâki

Fr.: précession absidiale   

advance of perihelion, → relativistic precession.

apsidal; → precession.

arc of separation
  کمان ِ جدایی   
kamân-e jodâyi

Fr.: arc de séparation   

The difference in → right ascension between the → Sun and the → Moon, measured in degrees.

arc; → separation.

arc of vision
  کمان ِ دید   
kamân-e did

Fr.: arc de vision   

The → angular  → difference in → altitude between the → Sun and the → Moon.

arc; → vision.

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