An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 71 Search : angle
aberration angle
  زاویه‌ی ِ بیراهش   
zâviye-ye birâheš

Fr.: angle d'aberration   

The angle tilt required by the → stellar aberration phenomenon in order that a moving telescope points directly to a star.

aberration; → angle.


Fr.: angle   

The figure formed by two lines extending from a common point; the figure formed by two intersecting planes (dihedral angle).

L. angulum (nominative angulus) "corner," a dim. form from PIE *ang-/*ank- "to bend". Cf. Skt. ankah "hook, bent," Gk. angkon "elbow," angkura "anchor," Lith. anka "loop," O.E. ancleo "ankle," O.H.G. ango "hook," Av. ank- "curved, crooked," Av. angušta- "toe," Mod.Pers. angošt, angol, angul "finger".

Zâviyé from Ar. zâwiyat "corner, angle".

angle of deviation
  زاویه‌ی ِ کژرفت   
zâviye-ye kažraft

Fr.: angle de déviation   

The angle between the → incident ray of light entering an → optical system (such as a prism) and the → refracted ray that emerges from the system. Because of the different indices of refraction for the different wavelengths of visible light, the angle of deviation varies with wavelength.

angle; → deviation.

angle of emergence
  زاویه‌ی ِ زمرچش   
zâviye-ye zomarceš

Fr.: angle d'émergence   

The angle of the light coming out of a medium. For a medium with parallel sides (such as a glass slab) it is equal to the angle of incidence.

angle; → emergence.

angle of incidence
  زاویه‌ی ِ فتاد   
zâviye-ye fotâd

Fr.: angle d'incidence   

The angle formed between a ray of light striking a surface and the normal to that surface at the point of incidence. Also called → incidence angle.

angle; → incidence.

angle of inclination
  زاویه‌ی ِ درکیل   
zâviye-ye darkil

Fr.: angle d'inclinaison   

1) General: The angle between one plane and another, or the angle formed by a reference axis and a given line.
2) Binary systems: The angle between the plane of the orbit and the → plane of the sky.
3) Rotating stars: The angle between the → equatorial plane and the → plane of the sky.

angle; → inclination.

angle of minimum deviation
  زاویه‌ی ِ کژرفت ِ کمینه   
zâviye-ye kažraft kaminé

Fr.: angle de déviation minimale   

The angle between the light entering and exiting the prism when the light passing through the prism is parallel to the prism's base. Angle of minimum deviation (D) is used to measure the → index of refraction (n) of the prism glass, because: n = sin [(A + D)/2]/sin (A/2), where A is the → prism angle.

angle; → minimum; → deviation.

angle of prism
  زاویه‌ی ِ منشور   
zâviye-ye manšur

Fr.: angle de prisme   

prism angle.

angle; → prism.

angle of reflection
  زاویه‌ی ِ بازتاب   
zâviye-ye bâztâb (#)

Fr.: angle de réflexion   

The angle between the reflected ray and the normal to the reflecting surface.

angle; → reflection.

angle of refraction
  زاویه‌ی ِ شکست   
zâviye-yé šekast (#)

Fr.: angle de réfraction   

The angle between the direction in which a ray is refracted and the normal to the refracting surface.

angle; → refraction.

azimuthal angle
  زاویه‌ی ِ سوگانی   
zâviye-ye sugâni

Fr.: angle azimutal   

In → spherical coordinates, an angle measured from the x-axis in the xy-plane.

Azimuthal, adj. from azimuth; → angle.

blaze angle
  زاویه‌ی ِ بلیز   
zâviye-ye beliz

Fr.: angle de blaze   

The angle between the operating facet of the grooves and the overall plane of a diffraction grating.

blaze; → angle.

Angâl, zâviyée, → angle; belizblaze.

Bragg angle
  زاویه‌ی ِ براگ   
zâviye-ye Bragg

Fr.: angle de Bragg   

The grazing angle between an incident beam of X-rays and a given set of crystal planes for which the secondary X-rays from the planes combine to give a single beam.

Bragg's law; → angle.

Brewster angle
  زاویه‌ی ِ بروستر   
zâviye-ye Brewster (#)

Fr.: angle de Brewster   

The → angle of incidence for which the sum of the incident angle and the → angle of refraction is 90°. The value of Brewster's angle for glass is 57° and for water is 53°. Same as → polarizing angle.

Brewster's law; → angle.

complementary angle
  زاویه‌ی ِ اسپرنده   
zâviyé-ye osporandé

Fr.: angle complémentaire   

Any angle that when added to another one creates a 90° angle.

complementary; → angle.

compound angle
  زاویه‌ی ِ چندساخت   
zâviye-ye candsâxt

Fr.: angle composé   

An angle that results from the combination of two other angles. These angles are expressed by → compound angle formulae.

compound; → angle.

compound angle formula
  دیسول ِ زاویه‌ی ِ چندساخت   
disul-e zaviye-ye candsâxt

Fr.: formule d'angle composé   

One of eight equations that give the → trigonometric functions of → compound angles.
sin(A± B) = sinA.cosnd angleB± cosA.sinB
cos(A + B) = cosA.cosB - sinA.sinB
cos(A - B) = cosA.cosB + sinA.sinB
tan(A + B) = (tanA + tanB)/(1 - tanA.tanB)
tan(A - B) = (tanA - tanB)/(1 + tanA.tanB).

compound; → angle; → formula.

congruent angles
  زاویه‌های ِ دمساز   
zâviyehâ-ye damsâz

Fr.: angles congrus   

Two angles if they have the same measure. Congruent angles may lie in different orientations or positions.

congruent; → angle.

congruent triangles
  سه‌برهای ِ دمساز   
sebarhâ-ye damsâz

Fr.: triangles congrus   

Two triangles when all corresponding sides and interior angles have the same measure. The triangles will have the same shape and size, but one may be a mirror image of the other.

congruent; → triangle.

conjugate angles
  زاویه‌ها‌ی ِ همیوغ   
zâviyehâ-ye hamyuq

Fr.: angles conjugués   

Two angles whose sum is 360° or 2π radians.

conjugate; → angle.

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