Fr.: cercle à réflexion
An instrument for measuring angular distances, based on the same principle as the → octant, but with a full circular limb divided into 720°. It was invented in 1752 by the German astronomer Johann Tobias Mayer (1723-1762) to improve on the octant which often gave wrong results because of incorrect graduations. The instrument consisted of an index arm and a small telescope, both pivoted centrally. In practice, the index arm is first set to zero, and the telescope rotated until the two images of a star are seen in coincidence (the one directly, the other by double reflection). Then the index arm is freed, and rotated until the other object is seen in coincidence after double reflection. The angle has now been measured, but the double operation is repeated several times, and the final angle divided by the number of repetitions to find a mean value. Hence, the instrument was sometimes called a "repeating circle." The reflecting circle had little success because it was heavy and uncomfortable to use. Its improved form is called → Borda circle.
teleskop-e bâztâbi (#), durbin-e ~ (#)
Fr.: télescope réflecteur
A telescope in which the image is produced by reflection of light by a concave mirror.
Verbal noun of → reflect.
hamgar-e bâztâb (#)
Fr.: coefficient de réflexion
The ratio given by the → amplitude (or energy) of a reflected wave divided by the amplitude (or energy) of the incident wave.
Fr.: facteur de réflexion
The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.
Fr.: nébuleuse par réflexion
A type of nebula that is visible from its reflection of starlight. Bright stars near reflection nebulae emit light into the region that is reflected by the large amount of dust there. The size of the dust grains causes blue light to be reflected more efficiently than red light, so these reflection nebulae frequently appear blue in color.
Fr.: réfléchissant, réflecteur
That reflects; reflecting. Of or pertaining to reflection.
From → reflect + -ive a suffix of adjectives and nouns of adjectival origin.
Bâztâbi adj. of bâztâb, → reflection.
1) bâzdisi; 2) bâzdisida,
Fr.: 1) réforme; réformer
1) (n.) The improvement, amendment, or reorganization of something
that is considered to be wrong, ineffective, or unsatisfactory;
e.g. calendar reform.
From M.E. reformen, from M.Fr. reformer, from O.Fr., from L. reformare "to form again, change, alter," from → re- "again" + formare "to form," from forma "form, mold, shape, case," origin unknown.
1) Bâzdisi, from bâz- "again," → re-, +
dis, disé "form, appearance," (variants -diz, -diš (tandis
"body form, like a body; effigy; statute;" mâhdis "moon-like;"
šabdiz "night color; a horse of
dark rusty color;" andiš- "to think, contemplate"); Mid.Pers.
dêsag "form, appearance," dêsidan
"to form, build;" Av. daēs- "to show," daēsa- "sign, omen;"
cf. Skt. deś- "to show, point out;" PIE *deik- "to show"
(cf. Gk. deiknumi "to show,"
dike "manner, custom;" L. dicere "to utter, say;" O.H.G. zeigon,
Ger. zeigen "to show;" O.E. teon "to accuse," tæcan "to teach")
+ -i noun suffix.
To alter the course of a wave of light, sound, etc. when the wave crosses the boundary between this medium and another through which it travels at a different speed.
From L. refractus, p.p. of refringere, → refraction.
Verb of šekast, → refraction.
partow-e šekasté (#)
Fr.: rayon réfracté
A → light ray that undergoes a change of velocity and direction, as a result of interaction with the material medium in which it travels.
Fr.: réfraction; à réfraction
manšur-e šekastgar (#)
Fr.: prisme réfractant
A prism that is used as a dispersing element in a spectrograph.
teleskop-e šekasti (#), durbin-e ~ (#)
Fr.: lunette astronomique
A telescope in which an image is formed by the refraction of light through a lens or lens system.
1) Optics: The change of direction which a beam of light undergoes as it
enters a medium of different → refractive index.
From L.L. refractionem (nominative refractio) "a breaking up," from L. refractus, p.p. of refringere "to break up," from re- "back" + combining form of frangere "to break," from PIE base *bhreg- "to break" (cf. Goth. brikan, O.E. brecan "to break;" Lith. brasketi "crash, crack").
Šekast, past stem of šekastan "to break, split;" Mid.Pers. škastan "to break;" Av. scind-, scand "to beak, cleave;" Proto-Iranian *skand- "to break, cleave;" PIE sken- "to cut off."
Fr.: indice de réfraction
Of any optical medium, the ratio of the → speed of light in vacuum (c) to that in the medium (v): n = c/v. The refractive index for vacuum, by definition, is 1. The refractive index of air is 1.00029 at standard temperature (25 °C) and pressure (1 atm). The refractive index of a medium depends on the wavelength of refracted wave. With light waves, n increases as the wavelength decreases. → Snell's law can be used to derive n. Same as → index of refraction.
Same as → refracting telescope.
Agent noun of refract, → refraction.
From refract, → refraction + adj. suffix -ory.
Sarkeš "refractory, disobedient, rebellious, stubborn,"
literally "withdrw, remove head," from sar
"head" (variants soru, sorun "horn,"
karnâ "a trumpet-like wind instrument," variant sornâ "a wind instrument;"
Mid.Pers. sar "head," sru "horn;" Av. sarah- "head,"
srū- "horn, nail;" cf. Skt. śiras- "head, chief;"
Gk. kara "head," karena "head, top," keras "horn;"
L. cornu "horn," cerebrum "brain;"
P.Gmc. *khurnaz (Ger. Horn, Du. horen;
cognate with E. horn, as above, from PIE *ker- "head, horn;"
O.E. horn "horn of an animal," also "wind instrument;"
E. horn); PIE base *ker-
"head, horn, top, summit")
+ keš present stem of kešidan, kašidan
"to draw; withdraw, remove" (dialectal Yaqnavi xaš "to draw," Qomi xaš
"streak, stria, mark," Lori kerr "line;"
Av. karš- "to draw; to plow," karša-
"furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;"
cf. Skt. kars-, kársati "to pull, drag, plow;"
Gk. pelo, pelomai "to move, to bustle;" PIE base kwels-
An act or instance of refusing.
Nežan, from ne- "down, below," → ni-, + žan variant of zan present stem of zadan "to hit, strike," variants Zazaki jinen-, Gazi žen-/žent "to beat, hit," Baluchi jat/jan- "to strike, hit," Awromani žanây/-žan- "to shut (the door)," Pashto -žan "to chop, mince," → beat.