An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 417
field equation
  هموگش ِ میدان   
hamugeš-e meydân

Fr.: équation de champ   

In a physical theory, an equation that describe how a fundamental force interacts with matter. Einstein's equations of → general relativity are called field equations since they describe the → gravitational field. Similarly, → Maxwell's equations describe the electromagnetic field.

field; → equation.

field galaxy
  کهکشان ِ میدان   
kahkešân-e meydân

Fr.: galaxie de champ   

A galaxy that lies in the direction of a → cluster of galaxies, but is not a member of the cluster. Field galaxies are rare, less than about 5% of all galaxies.

field; → galaxy.

field horizontal branch star
  ستاره‌ی ِ شاخه‌ی ِ افقی ِ میدانی   
setâre-ye šâxe-ye ofoqi-ye meydâni

Fr.: étoile de la branche horizontal du champ   

A → horizontal branch star with high velocity.

field; → horizontal; → branch; → star.

field lens
  عدسی ِ میدان   
adasi-ye meydân

Fr.: lentille de champ   

A lens placed at or near the focal plane of a telescope to create an image of the primary mirror inside the instrument.

field; → lens.

field object
  بر‌آخت ِ میدان   
barâxt-e meydân

Fr.: objet de champ   

An astronomical object that is seen in the direction of a group but not physically belonging to the group. → field galaxy.

field; → object.

field of force
  میدان ِ نیرو   
meydân-e niru (#)

Fr.: champ de force   

The region of → space surrounding a body, such as a mass of → matter, a → charged particle, or a → magnet, within which it can exert a → force on another similar body not in contact with it.

field; → force.

field of view
  میدان ِ دید   
meydân-e did (#)

Fr.: champ de vue   

The entire angular expanse of the sky viewed by an optical instrument.

field; → view.

field rotation
  چرخش ِ میدان   
carxeš-e meydân

Fr.: rotation de champ   

The effect of the Earth's rotation on the position of the image formed on the → focal plane of a telescope during long exposures. In the case of → equatorial mounting, the image remains fixed, whereas it turns continuously with an → altazimuth mounting. In the latter case the image motion must be compensated by an appropriate mechanism, → field rotator.

field; → rotation.

field rotator
  چرخاننده‌ی ِ میدان   
carxânande-ye meydân

Fr.: rotateur de champ   

A device used on a telescope to correct for the → field rotation while tracking an object.

field; → rotator.

field star
  ستاره‌ی ِ میدان   
setâre-ye meydân

Fr.: étoile de champ   

A star that does not belong to a stellar cluster, but happens to be adjacent to it.

field; → star.

field stop
  دریچه‌ی ِ میدان   
darice-ye meydân

Fr.: diaphragme de champ   

A diaphragm located at an image plane of an optical system that determines the size and shape of the image. → aperture stop.

field; → stop.

field theory
  نگره‌ی ِ میدان   
negare-ye meydân

Fr.: théorie des champs   

1) A theory which uses the concept of → field to describe physical phenomena. It consists of two types: → classical field theory and → quantum field theory.
2) Math.: A branch of mathematics which studies the → fields.

field; → theory.

šekl (#)

Fr.: figure   

The precise curve required on the surface of an optical element, especially the mirror of a reflecting telescope.

From O.Fr. figure, from L. figura "a shape, form."

Šekl from Ar. šakl "figure."



The final stage of mirror making, a process of altering the mirror's shape into the one required for proper function. → grinding; → polishing.

Figuring, noun of → figure.

Šekldahi, "giving form," from šekl, → figure + dahi, a verbal noun of dâdan "to give," from Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" cf. Skt. dadáti "he gives," Gk. didomi "I give," tithenai "to put, set, place;" L. dare "to give, offer;" facere "to do, to make;" Rus. delat "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do." PIE base *dhe- "to put, to do."

rešté (#)

Fr.: filament   

1) A long tongue of a relatively cold matter (10,000 K), suspended in the → solar corona (2 million K). Filaments seem dark in the Hα light when they are seen projected on the solar disk; at the limb they look as what they actually are: → prominences.
2) Electricity, Electronics: In electric light bulbs and thermionic valves, a wire of metal of high melting point, which is heated by the passage of an electric current.
3) Cosmology: → cosmic filament.

From Mod.L. filamentum, from L.L. filare "to spin, draw out in a long line," from L. filum "thread," from PIE base *gwhi- "thread, tendon;" cf. Gk. bios "bow;" Skt. jiyā- "bow-string;" Av. jiiā- "bow-string;" Mod.Pers. zeh "string, bow-string" (dialectal Qomi zij "mason's cord"); Arm. jil "string, line;" Lith. gijà "thread;" Russ. žica "thread."

Rešté "thread, line, file," from reštan, ristan "to spin;" Mid.Pers. 'rws- "to turn to," abrešom "silk;" Sogdian rwyšt "spun;" Av. uruuaēs- "to twist, turn;" Proto-Iranian *uris- "to turn, spin."

filamentary nebula
  میغ ِ رشته‌ای   
miq-e rešteyi

Fr.: nébuleuse filamentaire   

A nebula, generally ionized, consisting of filament-like structures of gas, such as the Veil Nebula (NGC 6960) or the supernova remnant IC 443.

Filamentary adj. of → filament; → nebula.

filar micrometer
  ریزسنج ِ زهی   
riz-sanj-e zehi

Fr.: micromètre filaire   

An instrument used with a telescope for accurately measuring small angular separations between two celestial bodies (as between binary stars). The instrument consists of two parallel fine wires with one wire being fixed and the other movable by means of a finely threaded screw.

Filar, from L. fil(um) "a thread" (see the paragraph below) + -ar variant of the adjective-forming suffix → -al; → micrometer.

Kehsanj, → micrometer; zehi adj. of zeh "string, bow-string;" Mid.Pers. zih "bow-string," zig "string; astronomical table" (loaned into Ar. as zij); Av. jiiā- "bow-string;" cf. Skt. jiyā- "bow-string;" Gk. bios "bow;" L. filum "thread;" Arm. jil "string, line;" Lith. gijà "thread;" Russ. žica "thread;" PIE base *gwhi- "thread, tendon."

parvandé (#)

Fr.: fichier   

In computer science, a collection of related data or program records stored on a support.

From M.E. filen, from M.F. filer "to string documents on a thread," O.F. filer "to wind or spin thread," from L.L. filare "to spin, draw out in a long line," from L. filum "thread," from PIE base *gwhi- "thread, tendon;" cf. Gk. bios "bow;" Skt. jiyā- "bow-string;" Av. jiiā- "bow-string;" Mod.Pers. zeh "bow-string;" Arm. jil "string, line," Lith. gijà "thread;" Russ. žica "thread."

Parvandé "file," initially "a bundle, roll, truss (of clothes)," from Mid.Pers. parwastan, parwand- "to surround, enclose, contain, comprise," from par-, variants far-, par-, pirâ- "around, about" (Mid.Pers. pêrâ; O.Pers. pariy "around, about," Av. pairi "around, over;" Skt. pari; Indo-Iranian *pari- "around;" PIE base *per- "through, across, beyond;" cf. Gk. peri "around, about, beyond;" L. per "through") + vand-/band- stem of vastan/bastan "to bind, shut;" O.Pers./Av. band- "to bind, fetter," banda- "band, tie" (cf. Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind;" Ger. binden; E. bind).

filling factor
  کروند ِ پُری   
karvand-e pori

Fr.: facteur de remplissage   

Of a molecular cloud or a nebula, the ratio of the volumes filled with matter to the total volume of the cloud.

Filling, from fill, from O.E. fyllan, from P.Gmc. *fullijan (cf. Du. vullen, Ger. füllen "to fill"), a derivative of adj. *fullazfull; → factor.

Karvand, → factor; pori, from por, → full.

pâlâyé (#)

Fr.: filtre   

1) General: A device for separating the constituents of a system according to a physical property. In particular, a device for removing solid matter suspended in a liquid by forcing the suspension through a material which retains the solid matter while allowing the liquid to pass.
2) Optics: A device for transmitting electromagnetic radiation with restricted ranges of wavelength. Two types are generally used, → glass filters and → interference filters. See also → neutral density filter.
3) Electronics: A circuit or equipment allowing the transmission of desired frequencies and the elimination of others.

From M.L. filtrum "felt," which was used to strain impurities from liquid, from W.Gmc. *filtiz.

Pâlâyé, from pâlây present stem of pâludan "to filter, purify;" Mid.Pers. pâludan, pâlây- "to strain, filter, purify," from Proto-Iranian *pari-harz-, from prefix *pari- "around," → peri-, + harz- "to let go, release;" cf. Av. pairi.harəz- "to filter," from pairi- "around, over" (cf. Skt. pari; Gk. peri "around, about, beyond;" L. per "through;" PIE base *per- "through, across, beyond") + harəz- "to release" (especially water, liquid; cf. Chorasmian pžy- "to purify, filter;" Arm. (loanword) parzel "to filter, purify;"

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