An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 230
vernal point
  نقطه‌ی ِ بهاری   
noqte-ye bahâri

Fr.: point vernal   

The intersection point between the → celestial equator and the → ecliptic from where the Sun apparently enters into the northern celestial hemisphere.

vernal; → point.

vernal-equinox year
  سال ِ هموگان ِ بهاری   
sâl-e hamugân-e bahâri

Fr.: année d'équinoxe vernal, année vernale   

The time interval between two successive passages of the Sun, when the true longitude of the Sun is considered. In other words, the interval during which the Sun's true longitude increases by 360 degrees. Its mean length for the epoch J2000.0 is 365.24236460 real solar days (approximately 365.2424 days). The vernal-equinox year, on which the Iranian calender is based, should not be confused with → tropical year. See also: A concise review of the Iranian calendar. → Iranian calendar

vernal; → equinox; → year.

vernier (#)

Fr.: vernier   

A small movable scale running parallel to the main graduated scale in certain measuring instruments, such as the → sextant, used to obtain a fractional reading of one of the divisions on the main scale. Also known as Vernier scale.

After the French mathematician Pierre Vernier (1580-1637), who invented the scale in 1631.


Fr.: version   

A particular form or variant of something.
An account of something, given from a specific point of view.

M.E., from M.Fr. version, from M.L. versionem (nominative versio) "a turning," from p.p. stem of L. vertere "to turn;" cognate with Pers. gardidan "to change," as below.

Gardâk, present stem of gardidan "to change, to turn" (Mid.Pers. vartitan "to change, to turn;" Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend") + -âk noun suffix.


Fr.: vertex, sommet   

Plural form: vertices.
1) Astro.: A point in the → celestial sphere toward which or from which the common motion of a group of stars is directed.
2) Math.: The → point where two → sides of a → plane figure or an → angle  → intersect.
3) In → graph theory, any of the points of which graphs are formed. Same as → node.

From L. vertex "highest point," literally "the turning point," originally "whirlpool," from vertere "to turn," cognate with Pers. vartidan, gardidan, → version.

Târak, variant târ "top, vertex, head, the middle of the head;" cf. Sogd. târ "summit, forehead;" Yaghnobi tôr(k) "the back of the head;" Yazghulami tur "summit, head;" Proto-Ir. *starH- "to spread," → expand; PIE *ster- "spread, extend."

hajin (#)

Fr.: vertical   

1) The apparent → direction of → gravity at the point of observation.
2) Being in a position or direction → perpendicular to the → plane of the → horizon. See also → normal.

Vertical, literally "of or at the vertex, directly overhead," from M.Fr. vertical, from L.L. verticalis "overhead," from L. vertex (genitive verticis) "highest point"

Hajin, from haj, variant hac "anything held vertical, erected in the manner of a spear" (Dehxodâ), may be from Proto-Ir. *hac- "to follow;" cf. Av. (+ *ā-) hac- "to stick to;" Mid.Pers. hâz- "to lead, guide;" → associate.

vertical circle
  پرهون ِ هجین، دایره‌ی ِ ~   
parhun-e hajin, dâyere-ye ~

Fr.: cercle vertical   

The greater circle on the celestial sphere which passes through → zenith, → nadir, and the star and whose plane is perpendicular to the plane of horizon. Same as → azimuth circle.

vertical; → circle.

vertical scaling
  مرپلش ِ هجین   
marpeleš-e hajin


In computer science, a scaling in which the processing power of the same node/system is increased by increasing/decreasing its resources (CPU, memory, etc.). See also → horizontal scaling.

vertical; → scaling.


Fr.: sommets, vertex   

Plural of → vertex.


besyâr (#)

Fr.: très   

In a high degree. → Very Large Telescope (VLT); → very massive star; → very high frequencies (VHF).

M.E.; O.Fr verai "true;" L. verax (genitive veracis) "truthful," from verus "true."

Besyâr, from bas "many, much" (Mid.Pers. vas "many, much;" O.Pers. vasiy "at will, greatly, utterly;" Av. varəmi "I wish," vasô, vasə "at one's pleasure or will," from vas- "to will, desire, wish").

very high frequencies (VHF)
  بسامدهای ِ بسیار بالا   
basâmadhâ-ye besyâr bâlâ

Fr.: très hautes fréquences   

Radio frequencies in the range 30 to 300 mega Hz.

very; → high; → frequency.

Very Large Array (VLA)
  آرست ِ بسیار بزرگ   
ârast-e besyâr bozorg

Fr.: Very Large Array (VLA)   

A radio interferometer consisting of 27 antennas, each 25 m in diameter, in a Y-shaped configuration. It is located about 100 km west of Socorro, New Mexico, and is operated by the United States National Radio Astronomy Observatory. The VLA has the resolution of a single antenna 36 km wide and the sensitivity of a dish 130 m across.

very; → large; → array.

Very Large Baseline Array (VLBA)
  آرست با پایه-خط ِ بسیار بزرگ   
ârast bâ pâye-xatt-e besyâr bozorg

Fr.: Very Large Baseline Array (VLBA)   

A network of ten 25-m radio telescopes for → very-long-baseline interferometry (VLBI), operated by the U.S. National Radio Astronomy Observatory. Eight of the VLBA telescopes are distributed across the continental United States, while the other two are in Hawaii and the Virgin Islands, giving a maximum baseline of about 8,000 km and a resolution better than a milliarcsecond at its shortest wavelength.

very; → large; → baseline; → array.

Very Large Telescope (VLT)
  تلسکوپ ِ بسیار بزرگ   
tleskop-e besyâr bozorg

Fr.: Très Grand Télescope, VLT   

An observing facility consisting of four 8.2 m telescopes, with the combined collecting area of a 16 m mirror, owned and operated by the European Southern Observatory at an altitude of 2635 m at the Paranal Observatory in Chile. The four reflecting unit telescopes are called Antu "Sun" in the language of Chile's indigenous Mapuche people, Kueyen "Moon," Melipal "Southern Cross," and Yepun "Venus." Each unit is equipped with several sophisticated instruments. The light of the individual telescopes can be combined using interferometric techniques to achieve superior resolution. → VLT Interferometer (VLTI). The wavelength range covered by the VLT is extremely wide, ranging from deep ultraviolet to mid-infrared.

very; → large; → telescope.

very late thermal pulse (VLTP)
  تپه‌ی ِ گرمای ِ بسیار دیر   
tape-ye garmâyi-ye besyâr dir

Fr.: flash de l'hélium très tardif   

In evolutionary models of → post-asymptotic giant branch stars, the occurrence of the helium shell burning when the star has reached the → white dwarf cooling track. This leads to the possibility of a violent → helium shell flash and expansion on a time-scale of ≤ 10 years. The rapid expansion and prompt change in surface composition observed in → Sakurai's Object are thought to be due to such a very late thermal pulse.

very; → late; → thermal; → pulse.

very low-mass star
  ستاره‌ی ِ بسیار کم‌جرم   
setâre-ye besyâr kamjerm

Fr.: étoile de très faible masse   

A star with a typical mass of one-hundredth of the mass of the Sun (→ solar mass) and a luminosity of about one-millionth that of the Sun (→ solar luminosity). Same as → brown dwarf.

very; → low; → mass; → star.

very massive star
  ستاره‌ی ِ بسیار پرجرم   
setâre-ye besyâr porjerm

Fr.: étoile très massive   

A star of mass around 100 → solar masses. See also: → supermassive star, → massive star, → canonical upper limit.

very; → massive; → star.

very small grain (VSG)
  دانه‌ی ِ بسیار کوچک   
dâne-ye besyâr kucak

Fr.: très petit grain   

A special type of carbonaceous → interstellar dust grains with a size ranging from 10 to 150 Å and consisting of tens to hundreds of atoms. In contrast to → big grains, VSGs are not in → thermal equilibrium. They can be heated to very high temperatures (~ 1000 K) by the absorption of a single photon. It is thought that VSGs are clusters of → PAH.

very; → small; → grain.

very-long-baseline interferometry (VLBI)
  اندرزنش‌سنجی با پایه-خط ِ بسیار بزرگ   
andarzanešsanji bâ pâye-xatt-e besyâr bozorg

Fr.: interférométrie à très longue base   

A technique in radio interferometry in which the individual telescopes are not directly connected together, but instead make their observations separately with very accurate timings. The data are later sent to a central correlator to be combined. With this technique the individual telescopes can be arbitrarily far apart, and so the technique provides the highest resolution images in astronomy, typically down to a few milliarcseconds.

very; → large; → baseline; → interferometry.

  ۱) رگ؛ ۲) آوند   
1) rag (#); 2) âvand

Fr.: vaisseau   

1) A tube or duct, as an artery or vein, containing or conveying blood or some other body fluid.
2) Botany: A duct formed in the xylem, composed of connected cells that have lost their intervening partitions, that conducts water and mineral nutrients (

M.E., from O.Fr. vessel "container, receptacle; ship," from L.L. vascellum "small vase or urn," also "a ship," alteration of L. vasculum, diminutive of vas "vessel."

1) Rag "blood vessel, vein; lineage, race, stock," from Mid.Pers. rag, from Proto-Iranian *raha-ka-, from *raha- "liquid, essence," + suffix -ka-; cf. Av. ranhā- "name of a mythical stream;" Skt. rása- "juice (of plants), liquid, essence," rásavant-, rasin- "juicy;" L. ros "dew;" Lith. ràsa "dew;" O.C.S. rosa "dew."
2) Âvand "vessel," contraction of âbvand, literally "water utensil," from âb, → water, + vand "vessel, vase, cup," from bastan "to bind, shut," → shutter.

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