An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

An astronomical source in a field used as a reference for the detection of another object, astrometry, etc.

→ reference; → source.

1) To bring to a fine or a pure state; free from impurities.
2) To make more fine, subtle, or precise (Dictionary.com).

→ re-; → fine.

1) Pâludan "to purify, starin, → filter."
2) Nâzokidan, from nâzok "tender, delicate, subtle, neat," → fine.

1) Fineness or elegance of feeling, taste, manners, language, etc.
2) The act or process of refining. the quality or state of being refined.
3) An improved, higher, or extreme form of something.
Math.: A → set whose elements include the elements of a given set (Dictionary.com).

Verbal noun of → refine.

Any of a series of features occurring in the → light curve of → dwarf novae and → Soft X-ray Transient (SXT)s during → outburst decay. Reflares appear when the surface density Σ behind the cooling front is high enough to reach Σ_max. At the radius at which this happens, the disk becomes thermally unstable and a new heating front develops. This front propagates outward like an inside-out outburst, reheating the disk until Σ(R) ≤ Σ_min, when cooling can resume. The density in the cold region is depleted as matter is accreted during this process, and the following reflare occurs at smaller radii and have lower amplitudes (G. Dubus et al., 2001, A&A 373, 251).

→ re-; → flare.

To throw or bend back from a surface, specially light, sound, or heat.

M.E. reflecten, from L. reflectere "to bend back," from → re- "back" + flectere "to bend."

Bâztâbidan, from bâz-, → re- + tâbidan, variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "; to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."

1) Same as → reflection factor.
2) Computers: In optical character recognition, the relative value of the ink color compared to the background.

From → reflect + -ance

Bâztâbâyi, verbal noun from adj./agent noun bâztâbâ "reflecting."

A → light ray that is reflected from a surface.

→ reflect; → ray.

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.

→ reflection; → circle.

A telescope in which the image is produced by reflection of light by a concave mirror.

Reflecting, verbal adj. of → reflect; → telescope.

The return of radiation after striking a surface, without change in wavelength. If the surface is smooth, reflection is regular, otherwise it is diffuse. → diffuse reflection; → specular reflection.

Verbal noun of → reflect.

The ratio given by the → amplitude (or energy) of a reflected wave divided by the amplitude (or energy) of the incident wave.

→ reflection; → coefficient.

The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.

→ reflection; → factor.

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.

→ reflection; → nebula.

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.

Same as → reflectance; → reflection factor.

From → reflective + → -ity.

1) A → reflecting telescope.
2) A type of conducting surface or material used to → reflect radiant energy.

From reflect, → reflection, + → -or.

1) (n.) The improvement, amendment, or reorganization of something that is considered to be wrong, ineffective, or unsatisfactory; e.g. calendar reform.
2) (v.tr.) To change and improve by correction of faults, alteration, substitution, abolition, etc.

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.
2) Bâzdisidan infinitive from bâzdisi, as above.

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.

A → light ray that undergoes a change of velocity and direction, as a result of interaction with the material medium in which it travels.

→ reflect; → ray.

1) The action or result of the verb → refract.
2) Participial adjective of → refract.

From → refract + → -ing.