An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 20 Search : equator
celestial equator
  هموگار ِ آسمانی   
hamugâr-e âsmâni

Fr.: équateur céleste   

An imaginary great circle on the sky half-way between the → celestial poles. It is the projection of the → equator of the Earth on the sky.

celestial; → equator.

  هموگار، استوا   
hamugâr, estevâ (#)

Fr.: équateur   

The great circle on the surface of a body formed by the intersection of the surface with the plane passing through the center of the body perpendicular to the axis of rotation. → celestial equator.

From M.L. æquator "equalizer" (of day and night, as when the sun crosses the equator), from æquare "to make equal, equate" + -tor.

Hamugâr, from hamug, → equal + -âr suffix forming agent nous (as in parastâr) or contracted present stem of âvardan "to bring; to cause, to produce."

equator plane
  هامن ِ هموگاری   
hâmon-e hamugâri

Fr.: plan équatorial   

An imaginary plane → perpendicular to the → axis of a → sphere dividing the sphere into two congruent parts.

equator; → plane.

equator system
  راژمان ِ هموگاری   
râžmân-e hamugâri

Fr.: système équatorial   

A set of celestial coordinates based on the celestial equator as the primary great circle. The coordinates are → declination and → right ascension.

equator; → system.


Fr.: équatorial   

Of, pertaining to, or near an equator, especially the equator of the Earth.

From → equator + -ial, variant of → -al.

Hamugâri, from hamugâr, → equator, + adj. suffix -i.

equatorial bulge
  بر‌آمدگی ِ هموگاری   
barâmadegi-ye hamugâri

Fr.: bourrelet équatorial   

The excess of the equatorial diameter over the polar diameter of a celestial object, such as the Earth or the Moon.

equatorial; bulge, from O.Fr. bouge "leather bag," from L. bulga "leather bag," of Gaulish origin.

Barâmadegi, from barâmadan "to grow out; to emerge," from bar- "on, upon, up" (Mid.Pers. abar, O.Pers. upariy "above; over, upon, according to," Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + âmadan "to come" (Mid.Pers. âmadan; O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come").

equatorial coordinate system
  راژمان ِ هماراهای ِ هموگاری   
râžmân-e hamârâhâ-ye hamugâri

Fr.: système de coordonnées équatoriales   

An astronomical → coordinate system for indicating the positions of → celestial objects on the → celestial sphere. The system consists of two components, → right ascension and → declination. Right ascension is the angle between the → vernal equinox and the point where the → hour circle intersects the → celestial equator. The right ascension is always measured eastward from the vernal equinox, in the units of hours, minutes, and seconds. Declination is the angle between the celestial equator and the position of the star measured along the star's hour circle. It is measured in degrees, minutes, and seconds north or south of the celestial equator. By definition, the vernal equinox is located at right ascension 0h and declination 0°. Equatorial coordinates change with time due to the → precession of the Earth's → rotation axis.

equatorial; → coordinate; → system.

equatorial coordinates
  هماراها‌ی ِ هموگاری   
hamârâhâ-ye hamugâri

Fr.: coordonnées équatoriales   

Celestial coordinates in the → equator system.

equatorial, → coordinate.

equatorial mounting
  برنشاند ِ هموگاری   
barnešând-e hamugâri

Fr.: monture équatoriale   

A telescope mounting consisting of a polar axis pointed toward the celestial pole, and a declination axis supporting the instrument at right angles to the polar axis.

equatorial; → mounting.

equatorial plane
  هامن ِ هموگاری   
hâmon-e hamugâri

Fr.: plan équatorial   

The plane containing a celestial object's equator.

equatorial; → plane.

equatorial radius
  شعاع ِ هموگاری   
šo'â'-e hamugâri

Fr.: rayon équatorial   

Of a planet, the distance from the center to the equator. For Earth it is 6,378.1370 km. Jupiter has an equatorial radius 11.2 times Earth's value.

equatorial; → radius.

equatorial wind
  باد ِ هموگاری   
bâd-e hamugâri

Fr.: vent équatorial   

A slow, dense → stellar wind (high → mass loss rate) emanating from equatorial regions of a → B[e] star. The equatorial and → polar winds are the two main wind components in B[e] stars. The mechanism suggested to explain this wind morphology is the rotationally induced → bistability mechanism.

equatorial; → wind.

Galactic equator
  هموگار ِ کهکشان   
hamugâr-e kahkešân

Fr.: équateur galactique   

The great circle in the sky defined by the place of the → Galactic plane or the → Milky Way. At an angle of about 62°, the Galactic equator intersects the celestial equator at two points located in the constellations → Monoceros and → Aquila.

galactic; → equator.

geodetic equator
  هموگار ِ زمین‌سنجیک   
hamugâr-e zamin-sanjik

Fr.: équateur géodésique   

The plane swept out as the generating ellipse of the → reference ellipsoid rotates about its minor axis.

geodetic; → equator.

inclination of Earth's equator
  درکیل ِ هموگار ِ زمین   
darkil-e hamugâr-e zamin

Fr.: inclinaison de l'équateur terrestre   

obliquity of the ecliptic.

inclination; → Earth; → equator.

mean equator
  هموگار ِ میانگین   
hamugâr-e miyângin

Fr.: équateur moyen   

The orientation the Earth's equator would have if the nutation was subtracted.

mean; → equator.

precession of the equator
  پیشایان ِ هموگار   
pišâyân-e hamugâr

Fr.: précession de l'équateur   

That component of general precession caused by the combined effect of the Moon, the Sun and the planets on the equatorial protuberance of the Earth, producing a westward motion of the equinoxes along the ecliptic about 50'' per year. According to an IAU resolution adopted in August 2006, the present terminology replaces lunisolar precession.

precession; → equator.

real equator
  هموگار ِ هسیا   
hamugâr-e hasyâ

Fr.: équateur vrai   

Same as → true celestial equator.

real; → equator.

true celestial equator
  هموگار ِ آسمانی ِ راستین   
hamugâr-e âsmâni-ye râstin

Fr.: équateur céleste vrai   

The → celestial equator of date, which is the → great circle on the → celestial sphere perpendicular to the instantaneous axis of rotation of the Earth. Its interaction with the → ecliptic defines the → vernal equinox of date and the → autumnal equinox of date.

true; → celestial; → equator.

true equator
  هموگار ِ راستین   
hamugâr-e râstin

Fr.: équateur vrai   

Same as → true celestial equator.

true; → equtor.