An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 20 Search : mirror
concave mirror
  آینه‌ی ِ کاو   
âyene-ye kâv (#)

Fr.: miroir concave   

A mirror whose surface is curved inward and converges the light rays.

concave; → mirror.

converging mirror
  آینه‌ی ِ همگرا   
âyene-ye hamgerâ (#)

Fr.: miroir convergent   

A concave mirror that reflects a parallel beam into a convergent beam.

From → converge + → -ing; → mirror.

convex mirror
  آینه‌ی ِ کاو   
Âyene-ye kâv (#)

Fr.: miroir convexe   

A → spherical mirror with a reflecting surface curved outward, that is toward the object.

convex; → mirror.

deformable mirror
  آینه‌ی ِ وادیسیدنی   
âyene-ye vâdisidani

Fr.: miroir déformable   

A very thin mirror whose shape can be changed by the force applied by many small pistons behind the mirror. Such a mirror is used in the → adaptive optics technique to correct the → wavefront affected by the → atmospheric turbulence. See also → tip-tilt mirror.

deformable; → mirror.

Fresnel mirror
  آینه‌ی ِ فرنل   
âyene-ye Fresnel (#)

Fr.: miroir de Fresnel   

A pair of plane mirrors which are slightly inclined to one another. It is used for producing two coherent images in interference experiments.

Fresnel diffraction; → mirror.

Fresnel's mirrors
  آینه‌های ِ فرنل   
âyenehâ-ye Fresnel (#)

Fr.: miroirs de Fresnel   

Two plane mirrors, fitted side by side at a small angle, used to create two mutually → coherent sources in a famous → interference experiment first suggested by A. Fresnel. A point source reflected at the mirrors appears as a pair of → virtual light sources, positioned close together, which interfere with each other due to their → coherence. This arrangement removes the problem that two separate light sources do not produce observable interference on account of their incoherence. Same as Fresnel's double mirror. See also → Fresnel's biprism, → Lloyd's mirror.

Fresnel diffraction; → mirror.

liquid mirror
  آینه‌ی ِ آوه   
âyene-ye âvé

Fr.: miroir liquide   

A mirror composed of liquid, taking advantage of the parabolic shape of a spinning liquid and the fact that the mirror's focal length can be adjusted by altering the velocity at which the liquid's container spins.

liquid; → mirror.

Lloyd's mirror
  آینه‌ی ِ لوید   
âyene-ye Lloyd (#)

Fr.: miroir de Lloyd   

An optical arrangement in which light from a source is allowed to fall on a plane mirror at → grazing incidence. The light directly coming from the source interferes with the light reflected from the mirror forming an → interference pattern. See also → Fresnel's biprism, → Fresnel's mirrors.

After the Irish physicist Humphry Lloyd (1800-1881); → mirror.

âyene (#)

Fr.: miroir   

A smooth, highly polished surface, for reflecting light, that may be plane or curved. The actual reflecting surface is usually a thin coating of silver or aluminum on glass.

From O.Fr. mireor "a reflecting glass," earlier miradoir, from mirer "look at," from V.L. *mirare, from L. mirari "to wonder at, admire."

Âyene, from Mid.Pers. êwênag "mirror," from *âdênak, cf. Khotanese âyäna- "mirror," from Proto-Iranian *ādayana-, from prefix ā- + the root of Av. dā(y)- "to see," didāti "sees" (cf. Mod.Pers. didan "to see," Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen") + suffix -ak.

mirror blank
  گرده‌ی ِ آینه   
gerde-ye âyené

Fr.: disque miroir   

The material on which the reflecting coating is applied. It may be glass, quartz, or metal.

mirror; blank "a piece of metal ready to be drawn, pressed, or machined into a finished object," from M.E., from O.Fr. blanc (adj.) from Gmc; cf. O.E. blanca "white horse," O.H.G. blanch "bright, white."

Gerdé, → disk; âyené, → mirror.

mirror disk
  گرده‌ی ِ آینه   
gerde-ye âyené

Fr.: ébauche de miroir   

Same as → mirror blank.

mirror; → disk.

mirror testing
  آزمون ِ آینه   
âzmun-e âyené (#)

Fr.: test d'un miroir   

The observation and measurement of the flatness of a mirror surface. The process generally is done before coating so as not to damage the delicate coated surface. For coated and curved surfaces, non-contact methods are often employed, generally using interference techniques.

mirror; → test.

parabolic mirror
  آینه‌ی ِ سهمی   
âyene-ye sahmi (#)

Fr.: miroir parabolique   

A concave mirror that has the form of a paraboloid of revolution.

parabolic; → mirror.

plane mirror
  آینه‌ی ِ تخت   
âyene-ye taxt (#)

Fr.: miroir plan   

A mirror whose reflective surface is neither concave nor convex.

plane; → mirror.

pole of a mirror
  قطب ِ آینه   
qotab-e âyene

Fr.: pôle de mirroir   

The point where the → principal axis passes through the mirror.

pole; → mirror.

primary mirror
  آینه‌ی ِ نخستان   
âyene-ye noxostân

Fr.: miroir primaire   

In a → reflecting telescope, the first mirror that collects the light and focuses it to the → focal plane.

primary; → mirror.

secondary mirror
  آینه‌ی ِ دومان   
âyene-ye dovomân

Fr.: miroir secondaire   

The second reflecting surface in a → reflecting telescope. It directs the light either out a side opening of the tube (→ Newtonian telescope) or back toward a → focal point behind and through the → primary mirror (→ Cassegrain telescope). The secondary is usually suspended in the beam and therefore obstructs part of the primary.

secondary; → mirror.

segmented mirror
  آینه‌ی ِ برنکیده   
âyen-ye borankidé

Fr.: miroir segmenté   

A large telescope mirror consisting of smaller mirror segments designed to act as a single, larger reflecting surface. Because current monolithic mirrors cannot be constructed larger than about eight meters in diameter, the use of segmented mirrors is a key component for larger aperture telescopes.

Segmented, p.p. of → segment (v.); → mirror.

spherical mirror
  آینه‌ی ِ کره‌ای   
âyene-ye kore-yi

Fr.: miroir sphérique   

A mirror whose reflecting surface is a portion of a sphere. Spherical mirrors can be of two types: → concave mirror and → convex mirror.

spherical; → mirror.

tip-tilt mirror
  آینه‌یِ کج-و-راست-گر   
âyene-ye kaj-o-râst-gar

Fr.: miroir inclinable   

A rapidly moving → mirror used in → adaptive optics to correct overall movements of the incoming → wavefront of light caused by → atmospheric turbulence. The simplest form of adaptive optics is tip-tilt correction, which corresponds to correction of the tilts of the wavefront in two dimensions. This is done by tipping and tilting the mirror rapidly in response to overall changes in position of a reference star. See also → deformable mirror.

From, tip noun from tip (v.) "to overturn, upset," from M.E. typen "to upset, overturn" + tilt noun from tilt (v.) "to cause to lean, incline, slope, or slant," → tilt; → mirror.

Âyené, → mirror; kaj "turned aside; crooked, bent" (cf. Skt. kubja- "hump-backed, crooked," Pali kujja- "bent," L. gibbus "hump, hunch," Lith. kupra "hump") + -o- "and" + râstright + -gar agent noun suffix → -or.