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

1) General: The state or fact of being visible. → crescent Moon visibility, → Venus visibility.
2) Optics: → fringe visibility. See also: → visibility function, → visibility plane.
3) Meteo.: A measure of transparency of the atmosphere. The maximum horizontal distance at which objects can be identified. → turbidity.

→ visible + → -ity.

The → Fourier transform of a source's → brightness distribution, weighted by the characteristics of the → interferometer's antennas.

→ visibility; → function.

In → interferometry, the projection of a → baseline onto the plane normal to the source direction defining a vector in (u,v) space, measured in wavelength units.

→ visibility; → plane.

1) Capable of being seen by, or perceptible to, the human eye.
2) → visible light.

M.E., from O.Fr. visible, from L. visibilis "that may be seen," from visus, p.p. of videre "to see;" cognate with Pers. bin, present stem of didan "to see" (Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" cf. Skt. veda "I know;" Gk. oida "I know," idein "to see;" PIE base *weid- "to know, to see").

Diyâr "visible" in several dialects, e.g. štiyâni, Malâyeri, Širâzi, Tabari, related to didan "to see;" Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen."
Padidâr (→ phenomenon) and peydâ are both also related to dā(y)- (with prefixes).

That line where Earth and sky appear to meet, and the projection of this line upon the celestial sphere. Also known as the apparent horizon.

→ visible; → horizon.

The portion of the → electromagnetic radiation that can be seen by the human → eye. The → wavelengths extend from about 400 nm (violet) to 750 nm (red). The wavelengths of various colors of the visible spectrum are as follows: → violet: 390-455 nm; → blue: 455-492 nm; → green: 492-577; → yellow: 577-597; → orange: 597-622; → red: 622-780 nm.

→ visible; → light.

The portion of → electromagnetic spectrum corresponding to → visible light.

→ visible; → spectrum.

The act or power of sensing with the eyes. → averted vision; → acuity of vision.

M.E., from O.Fr. vision, from L. visionem (nominative visio) "act of seeing, sight, thing seen," from p.p. stem of videre "to see," cognate with Pers. bin, present stem of didan "to see" (Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" cf. Skt. veda "I know;" Gk. oida "I know," idein "to see;" PIE base *weid- "to know, to see").

Negâh, "look," from Mid.Pers. nikâh "look, glance, observation;" Proto-Iranian *ni-kas- "to look down," from ni- "down, below," → ni- (PIE), + *kas- "to look, appear;" cf. Av. nikā-, nikāta- (in the name of the 15-th nask) "that which is observed," ākas- "to look;" Mid.Pers. âkâh, Mod.Pers. âgâh "aware, knowing;" Skt. kāś- "to become visible, appear;" Ossetic kast/kaesyn "to look;" did, from didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").

1) Of or pertaining to seeing or sight.
2) → optical.

M.E., from L.L. visualis "of sight," from L. visus "sight," from visus, .pp. of videre "to see;" cognate with Pers. bin, present stem of didan "to see" (Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" cf. Skt. veda "I know;" Gk. oida "I know," idein "to see;" PIE base *weid- "to know, to see").

Didi, of or pertaining to did, from didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen"); didgâni, adj. of didgân, plural of didé, did "sight, eye; seen;" didâri, from didâr, from didan.

Same as → acuity of vision.

→ visual; → acuity.

A → binary system of stars whose components can be resolved telescopically and which have detectable orbital motion.

→ visual; → binary.

The → extinction in the visual range of the electromagnetic radiation.

→ visual; → extinction

The → apparent magnitude of a celestial body in the color sensitivity region of the human eye at a wavelength of 5600 Å. Visual magnitude is now essentially synonymous with V magnitude, which is determined photometrically.

→ visual; → magnitude.

1) The act of visualizing (→ visualize).
2) The presentation of → information on a → screen.

Verbal noun of → visualize.

Cašm-did, Mid.Pers. cašm-did "visible," Mod.Pers. cašm-didâr by Tusi, in Pers. translation of Sufi's "Book of Fixed Stars," from cašm "eye" (Mid.Pers. cašm, Av. cašman- "eye," ākas- "to look," from prefix ā- + Proto-Iranian *kas- "to look, appear," cf. Skt. cáksus- "seeing") + did past stem of didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").

1) To make → visual or → visible.
2) To present → image or → information on a → screen, usually a → computer  → display.

From → visual + → -ize; → visualization.

The science, production, and study of → grapes.

From L. viti(s) "vine" + → culture.

Mowkâri, from mow→ vine + kâri noun from kâštan "to cultivate," → culture.

An interferometer using a combination of the four 8.2 m VLT telescopes with the assistance of one or more of the the four 1.8 m Auxiliary Telescopes in order to achieve a very high spatial resolution. The system works in the visible and near- and mid-infrared wavelengths.

→ Very Large Telescope (VLT); → interferometer.

A set of words used by a → language, group, individual, or work, or in a field of → knowledge.

M.L. vocabularium "a list of words," from L. vocabulum "word, name, noun," from vocare "to name, call;" cognate with Pers. vâž, → word.

Vâžgân, from vâž, → word, + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, from Proto-Iranian *kāna-ka-.

The sharp edge of a fold of mucous membrane stretching along either wall of the larynx from the angle between the laminae of the thyroid cartilage to the vocal process of the arytenoid cartilage. Vibrations of these cords are used in voice production (The American Heritage).

→ voice; → cord.

The internal structure and all observable characteristics of a star (such as luminosity and temperature) are determined uniquely by its mass, chemical composition, and age. Same as → Russell-Vogt theorem.

Named after the German astronomer Heinrich Vogt (1890-1968) and the American astronomer Henry Norris Russell (1877-1957); → theorem.