An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < bel lon > >>

Number of Results: 35 Search : long
  پرگتیدن، پرگت داشتن   
pargetidan, parget dâštan

Fr.: appartenir   

1) (with preposition to) To be the property of.
2) (with preposition to) To be a part or adjunct of.

M.E. belongen, from be- intensive prefix, + longen "to go," from O.E. langian "pertain to, to go along with;" akin to Du. belangen, Ger. belangen; of unknown origin.

Pargetidan, literally "to surround, to relate with" (on the model of L. pertinere "pertain," Skt. parigraha- "surrounding; relation to"), from parget "to hold, seize, take around," from par- "around," → peri-, + get "to take, sieze," as in Tâleši gate "to take," Târi gata, Sorxeyi, Lâsgardi, Semnâni, Šâhmerzâdi -git- "take, seize," variants of gereftan "take, hold," → concept.

belongs to
  می‌پرگتد، پرگت دارد   
mipargetad, parget dârad

Fr.: appartient   

If x is an → element of a → set S, then x belongs to S and this is written x ∈ S.

Third person present verb of → belong.

celestial longitude
  درژنای ِ آسمانی   
derežnâ-ye âsmâni

Fr.: longitude céleste   

Angular distance to an object measured eastward along the → ecliptic from the → vernal equinox.

celestial; → longitude.

Derežnâ, → longitude; âsmânicelestial.

circle of longitude
  پرهون ِ درژنا   
parhun-e derežnâ

Fr.: méridien   

1) A great circle of the celestial sphere, from the pole to the ecliptic at right angles to the plane of the ecliptic.
2) A great circle on the terrestrial surface that meets the North and South poles and connects all places of the same longitude.

circle; → longitude.

Dulong-Petit law
  قانون ِ دولون-پتی   
qânun-e Dulong-Petit

Fr.: loi de Dulong et Petit   

The product of the → specific heat and → atomic weight of most solid elements at room → temperature is nearly the same. In other words, specific heat is constant for a solid and independent of temperature. Experiment shows that at moderate temperatures this law is satisfied for → crystals with rather simple structure. However, the law fails for crystals with more complex structures. More specifically the law cannot explain the variation of specific heat with temperature. The specific heat drops to zero as the temperature approaches 0 K. This behavior is explained only with the quantum theory. → Debye model.

Named after Pierre L. Dulong (1785-1838) and Alexis T. Petit (1797-1820), French chemists, who proposed the law in 1819. They collaborated in several important investigations, including studies of thermal expansion of gases and of liquids and the specific heats of substances; → law.

eastern elongation
  درازش ِ خاوری   
derâzeš-e xâvari

Fr.: élongation est   

The position of a planet when it can be seen in the western sky just after sunset.

eastern; → elongation.

ecliptic longitude
  درژنای ِ هورپهی   
derežnâ-ye hurpehi

Fr.: longitude écliptique   

One of the two coordinates in the → ecliptic system; the angle measured eastwards along the ecliptic from 0° to 360°, with the origin at the → vernal equinox.

ecliptic; → longitude.


Fr.: allonger   

To draw out to greater length; lengthen; extend.

From L.L. elongatus "lengthened out," p.p. of elongare "to make longer, to remove to a distance," from → ex- "out" + longus "long;" PIE base *dlonghos- "long;" cf. Av. darəga-, darəγa- "long," drājištəm "longest;" Mod.Pers. derâz "long," dir "late; long;" Skt. dīrghá- "long (in space and time);" Gk. dolikhos "long;" P.Gmc. *langgaz (Ger. lang; O.N. langr; M.Du. lanc; Goth. laggs "long;" E. long).

DerâzidanDerâzeš "to elongate," from derâz "long," Mid.Pers. drâz "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" PIE *dlonghos- "long," as above.

  درازیده، کشیده   
derâzidé, kešidé

Fr.: allongé   

Made longer; long and narrow.

Past participle of → elongate.

elongated orbit
  مدار ِ کشیده، ~ درازیده   
madâr-e derâzidé, ~ kašidé

Fr.: orbite allongée   

An → elliptical orbit with a high → eccentricity.

elongated; → orbit.


Fr.: élongation   

1) Increase in length per unit of original length.
2) The angular distance of a planet from the Sun as seen from the Earth. An elongation of 0° is called → conjunction; one of 180° is called → opposition; and an elongation of 90° is called → quadrature.

elongate; → -tion.

Galactic longitude
  درژنا‌ی ِ کهکشانی   
derežnâ-ye kahkešâni

Fr.: longitude galactique   

In the → Galactic coordinate system, the angle between the → Galactic Center and the projection of the object on the → Galactic plane. Galactic longitude, usually represented by the symbol lII, ranges from 0 degrees to 360 degrees.

galactic; → longitude.

general precession in longitude
  پیشایان ِ هروینِ درژنا   
pišâyân-e harvin-e derežnâ

Fr.: précession générale en longitude   

The secular displacement of the → equinox on the → ecliptic of date.

general; → precession; → longitude.

geocentric longitude
  درژنای ِ زمین-مرکزی   
derežnâ-ye zamin-markazi

Fr.: longitude géocentrique   

The same as → geodetic longitude.

geocentric; → longitude.

geodetic longitude
  درژنای ِ زمین‌سنجیک   
derežnâ-ye zamin-sanjik

Fr.: longitude géodésique   

The angle between the plane of the → geodetic meridian and the plane of of the geodetic meridian through the site of the → Airy transit circle at the Royal Greenwich Observatory.

geodetic; → longitude.

greatest eastern elongation
  بزرگترین درازش ِ خاوری   
bozorgtarin derâzeš-e xâvari

Fr.: plus grande élongation est   

The Greatest → elongation of an inferior planet occurring after sunset.

Superlative of → great; → eastern; → elongation.

greatest elongation
  بزرگترین درازش   
bozorgtarin derâzeš

Fr.: plus grande élongationt   

The largest → elongation of an inferior planet from the Sun. It may be → greatest eastern elongation or → greatest western elongation. The greatest elongation of Mercury is about 28°, and thus Mercury can only be observed 112 minutes after sunset or before sunrise. For Venus, it is about 47°, making it visible at most about 3 hours after sunset or before sunrise.

Superlative of → great; → eastern; → elongation.

greatest western elongation
  بزرگترین درازش ِ باختری   
bozorgtarin derâzeš-e bâxtari

Fr.: plus grande élongation ouest   

The Greatest → elongation of an inferior planet occurring before sunrise.

Superlative of → great; → western; → elongation.

libration in longitude
  هلازان ِ درژنایی   
halâzân-e derežnâyi

Fr.: libration en longitude   

A tiny oscillating motion of the → Moon arising from the fact that the Moon's orbit is not a precise circle but rather an → ellipse. Therefore, Moon is sometimes a little closer to the Earth than at other times, and as a result its → orbital velocity varies a bit. Since the Moon's rotation on its own axis is more regular, the difference appears as a slight east-west oscillation. Libration in longitude is the most significant kind of libration. It varies between about 4°.5 and 8°.1 because of gravitational perturbations in the Moon's orbit caused by the Sun.

libration; → longitude.

derâz (#)

Fr.: long   

1) Having considerable linear extent in space. → very-long-baseline interferometry (VLBI).
2) Having considerable duration in time. → long-period variable.

M.E. longe, O.E. lang, long, akin to O.H.G., Ger. lang "long," O.N. langr, M.Du. lanc, Goth. laggs "long," L. longus, → longitude.

Derâz "long," Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time)."

<< < bel lon > >>