An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 53 Search : sure
absolute measurement
  اندازه‌گیری ِ اوست   
andâzegiri-ye avast

Fr.: mesure absolue   

A measurement in which the comparison is directly with quantities whose units are basic units of the system. For example, the measurement of speed by measurements of distance and time is an absolute measurement, but the measurement of speed by a speedometer is not an absolute measurement. Note that the word absolute measurement implies nothing about → precision or → accuracy (IEEE Standard Dictionary of Electrical and Electronics Terms).

absolute; → measurement.

acoustic pressure
  فشار ِ صدا   
fešâr-e sedâ

Fr.: pression acoustique   

Same as → sound pressure.

acoustic; → pressure.


Fr.: assurer   

1) To declare earnestly to; inform or tell positively; state with confidence to.
2) To give confidence to; encourage.

M.E. as(e)uren, assuren, from O.Fr. aseurer, from L.L. assecurare, from as-, variant of → ad-, + secur-, → secure, + -a- thematic vowel, + -re infinitive suffix.

Âtenzidan, from â- intensive prefix, + tenz, → sure, + -idan infinitive suffix, → -ize.

calibration exposure
  نوردادِ کبیزش   
nurdâd-e kabizeš

Fr.: pose d'étalonnage   

An exposure obtained with an instrument mounted on the telescope using an artificial illuminating source in order to calibrate the instrument.

calibration; → exposure.

Nurdâd, → exposure; kabizeš, → calibration.

bandeš (#)

Fr.: clôture   

Math.: The property of a set in which the application of a given mathematical operation to any member of the set always has another member of the set as its result.
The intersection of all closed sets that contain a given set.

M.E., from M.Fr., from O.Fr. closure "that which encloses," from L. clausura "lock, fortress, a closing," from p.p. stem of claudere "to close."

Bandeš, verbal noun of bastan "to shut, bind; to clot; to form seed buds," from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie;" Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind," cf. Ger. binden, E. bind.

closure axiom
  بنداشت ِ بندش   
bondâšt-e bandeš

Fr.: axiome de clôture   

A basic rule in → group theory stating that if a and b are a group element then a * b is also a group element.

closure; → axiom.

closure phase
  فاز ِ بندش   
fâz-e bandeš

Fr.: clôture de phase   

In astronomical interferometry, a method using triplets of telescopes in an array to calculate the phase information and get over the effects of atmospheric turbulence. The method, used in high-resolution astronomical observations, both at radio and at optical wavelengths, allows imaging of complex objects in the presence of severe aberrations.

closure; → phase.

Coulomb pressure
  فشار ِ کولن   
fešâr-e Coulomb

Fr.: pression de Coulomb   

The repulsive interaction due to the → Coulomb energy between two ions. If the ionic charge is Z, then the Coulomb potential energy is Z2e2/a, where a is some typical separation between the ions. The Coulomb pressure is expected to become important when the ratio ΓC = Z2e2/akT is much larger than 1. In that case, Coulomb effects dominate those of → thermal agitation and the gas settles down into a → crystal.

Coulomb; → pressure.

dark exposure
  اسنهش ِ تاریکی، نورداد ِ ~   
osneheš-e târiki, nurdâd-e ~

Fr.: pose d'obscurité   

A → CCD frame obtained with closed → shutters in the absence of any light source, in order to estimate the → dark current of the → detector.

dark; → exposure.

deep exposure
  اسنهش ِ ژرف، نورداد ِ ~   
osneheš-e žarf, nurdâd-e ~

Fr.: pose profonde   

An exposure in which the detector shutter remains open for a relatively long time in order to bring out the weaker features of the observed object. In practice a deep exposure with a CCD detector is usually obtained from co-addition of shorter exposures.

deep; → exposure.

degeneracy pressure
  فشار ِ واگنی   
fešâr-e vâgeni (#)

Fr.: pression de dégénérescence   

Pressure in a degenerate electron or neutron gas. → degenerate matter.

degeneracy; → pressure.

dispersion measure
  اندازه‌ی ِ پاشش   
andâze-ye pâšeš

Fr.: mesure de dispersion   

A parameter used in radio astronomy which describes the amount of dispersion in a radio signal due to its passage through an intervening plasma. It is proportional to the product of the interstellar electron density and the distance to the source.

dispersion; → measure.


Fr.: mécontentement, déplaisir   

Dissatisfaction, disapproval, or annoyance.

dis-; → pleasure.

dynamic pressure
  فشار ِ توانیک   
fešâr-e tavânik

Fr.: pression dynamique   

A property of a moving → fluid defined by (1/2)ρv2 in → Bernoulli's law, where ρ is → density of fluid and v is → velocity. Dynamic pressure is the difference between → total pressure and → static pressure. Also called → velocity pressure. → ram pressure.

dynamic; → pressure.

emission measure
  اندازه‌ی ِ گسیل   
andâze-ye gosil

Fr.: mesure d'émission   

The product of the square of the electron density times the linear size of the emitting region (in parsecs).

emission; → measure.

  ۱) اسنهش؛ ۲) نورداد   
1) osneheš; 2) nurdâd

Fr.: pose, exposition   

1) The act of exposing; the fact or state of being exposed, → expose.
2) In optics, the total radiant energy incident on a surface per unit area. It is equal to the integral over time of the radiant flux density.

Verbal noun of → expose.

exposure meter
  اسنهش-سنج، نورداد-سنج   
osneheš-sanj, nurdâd-sanj

Fr.: posemètre   

In photography, an instrument used to measure the intensity of light from a scene to be photographed and to indicate the camera lens and shutter settings required to expose the film correctly.

exposure; → meter.

exposure time
  زمان ِ اسنهش، ~ نورداد   
zamân-e osneheš, ~ nurdâd

Fr.: temps de pose   

The length of time during which the receiver is irradiated.

exposure; → time.

Fermi pressure
  فشار ِ فرمی   
fešâr-e Fermi

Fr.: pression de Fermi   

Same as → degeneracy pressure.

fermi; → pressure.

hydrostatic pressure
  فشار ِ هیدروتوانیک   
fešâr-e hidrotavânik

Fr.: pression hydrodynamique   

The term ρgz in the → Bernoulli equation. It is not pressure in a real sense, because its value depends on the reference level selected.

hydrostatic; → pressure.

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