An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ab aba abs abs abs acc acc act act ada adi adv afo agi Ale alg Alk Aln alr alt amb ana And ang ani ano ant ant ape apo app aps arc arg Aro asc ass ast ast asy atm att aur ave axi > >>

Number of Results: 888

Fr.: apogalacticon   

The point at which a celestial body is farthest from the center of a galaxy; opposite of → perigalacticon.

From → apo- "away from, off" + galacticon, → galaxy.

From apâ, → apo-, + kahkašân, → galaxy.


Fr.: apogée   

The point in the orbit of the moon or an artificial satellite that is farthest from the terrestrial center and at which the body's velocity is at a minimum.

From Fr. apogée, from L. apogæum, from Gk. apogaion "away from the earth," from → apo- "off, away" + gaia/ge "earth." According to Dehxodâ, the term owj used in Persian is neither Ar. nor Skt. (contrary to the opinions of Khwarazi and Biruni respectively), but the corrupt form of the above Gk. term.

Apâzam, from apâ-, → apo-, + Av. zam- "the earth," Mid.Pers. zamig, Mod.Pers. zami, zamin "the earth;" cf. Skt. ksam, Gk. khthôn, khamai "on the ground," L. homo "earthly being" and humus "the earth" (as in homo sapiens or homicide, humble, humus, exhume); PIE root *dh(e)ghom "earth".

apogee eclipse
  گرفت ِ اپازمی   
gereft-e apâzami

Fr.: éclipse apogée   

An eclipse (of the Sun or Moon) which takes place when the Moon is at the → apogee of its orbit. The solar apogee eclipses, when they are not partial, are always → annular. The maximum duration of an apogee solar eclipse is 6h 15m (between the → first contact and the → fourth contact). The maximum duration of a lunar apogee eclipse, between the two exterior contacts of the Moon with the → penumbra, is 6h 18m (the maximum totality being 1h 44m) (M.S.: SDE).

apogee; → eclipse.

apogee full Moon
  پرمانگ ِ اپازم، پرماه ِ ~   
pormâng-e apâzam, pormâh-e ~

Fr.: pleine lune d'apogée   

The → full Moon when our natural satellite is at its farthest position from the Earth. The difference in apparent size with respect to the → perigee full Moon represents a difference in distance of just under 50,000 km between → apogee and → perigee, given the Moon's average distance of about 385,000 km. Also called → full micro Moon.

apogee; → full; → moon.


Fr.: apojove   

The → point in the → orbit of a → satellite of → Jupiter that is farthest from Jupiter's center.

apo- + jove, from L. Jovius "Jupiter," → Jovian.

Apollo asteroid
  سیارک ِ آپولون   
sayyârak-e Apollon

Fr.: astéroïde Apollon   

A member of a class of → near-Earth asteroids (NEAs) that have orbital → semi-major axes greater than that of the Earth (> 1 → astronomical unit) but → perihelion distances less than the Earth's → aphelion distance (less than 1.017 AU); thus, they cross the Earth's orbit when near the perihelia of their orbits. They are named for the prototype Apollo.

Apollo; → asteroid.

  اپامه، اپاماه   
apâmah, apâmâh

Fr.: apolune   

The point in a lunar orbit that is farthest from the center of the Lune. Also → apocynthion.

From → apo- "away from, off" + lune "moon," from L. luna; PIE *louksnâ- "moon," literally "luminous, bright;" compare with O.Pers. raucah-, Av. raocah- "light, luminous; daylight," Skt. roka "brightness, light," cognate with Gk. leukos "white, clear," L. lux "light" (also lumen, luna), PIE *leuk- "light, brightness". The Mod.Pers. words rowšan, raxšân "bright, clear," ruz "day," foruq "light," and afruxtan "to light, kindle" also belong to this family, as well as the E. light, Ger. Licht, and Fr. lumière.

Apâmah, apâmâh, → apocynthion.

dastgâh (#)

Fr.: appareil, dispositif   

An appliance or device for a particular purpose: an X-ray apparatus. An integrated group of materials or devices used for a particular purpose.

From L. apparatus "equipment, preparation," from p.p. of apparare "to prepare," from ad- "to" + parare "make ready".

Dastgâh "any manufacturing instrument, a loom; ustensils".

padidâr (#)

Fr.: apparent   

General: Open to view, visible; appearing as actual to the eye or mind.
In astronomy, observed.

O.Fr. aparant, from L. apparentem, pr.p. of apparere "to appear," from ad- "to" + perere "to come forth, be visible".

Padidâr "appearing, manifest," from padid "evident, clear, in sight," from Mid.Pers. patdit, from O.Pers./Av. patiy-/paiti "toward, against, back" (cp. Skt. prati- "near, toward, against, in return," Gk. proti, pros "face to face with, toward, in addition to") + O.Pers./Av. di-/dâ(y)- "to see" (Skt. dhi- "to think"), Mod.Pers. didan "to see".

apparent diameter
  ترامون ِ پدیدار، قطر ِ ~   
tarâmun-e padidâr, qotr-e ~

Fr.: diamètre apparent   

The angular diameter of a celestial body expressed in degrees, minutes, and seconds of arc, or in radians.

apparent; → diameter.

apparent distance
  دورا‌ی ِ پدیدار   
durâ-ye padidâr

Fr.: distance apparente   

The angular distance between two celestial bodies (e.g. the components of a binary star system), expressed in degrees, minutes and seconds of arc.

apparent; → distance.

apparent field
  میدان ِ پدیدار   
meydân-e padidâr

Fr.: champ apparent   

The angular diameter of the circle of light that the eye sees through an eyepiece.

apparent; → field.

apparent horizon
  افق ِ پدیدار   
ofoq-e padidâr

Fr.: horizon apparent   

The circle determined by the intersection of the heavens with a → cone whose → vertex is the → eye, and whose elements are tangent to lines of the Earth's surface. Same as → visible horizon. Assuming that there is no → atmospheric refraction, apparent horizon coincides with → geometric horizon. See also → sea horizon.

apparent; → horizon.

apparent magnitude
  برز ِ پدیدار   
borz-e padidâr

Fr.: magnitude apparente   

A measure of a star's observed brightness (opposed to → absolute magnitude); symbol m. It depends on the star's → intrinsic brightness, its distance from the observer, and the amount of → interstellar absorption. The brightest star → Sirius has an apparent magnitude of -1.46, while the weakest stars visible with the naked eye in the most favorable observation conditions have magnitudes of about +6.5. The stars of magnitudes less than +23 are measured by professional observatories, whereas those of magnitudes less than +30 by a telescope such as the → Hubble Space Telescope (M.S.: SDE).

apparent; → magnitude.

apparent noon
  نیمروز ِ پدیدار   
nimruz-e padidâr

Fr.: midi vrai   

The moment when the center of the Sun crosses the meridian. Same as true noon.

apparent; → noon.

apparent place
  جای ِ پدیدار   
jâ-ye padidâr

Fr.: position apparente   

Same as → apparent position.

apparent; → place.

apparent position
  نهش ِ پدیدار، جا‌ی ~   
naheš-e padidâr, jâ-ye ~

Fr.: position apparente   

1) The position on the celestial sphere at which a heavenly body would be seen from the Earth at a particular time.
2) A position given by the coordinates calculated for a star, if it were seen from the Earth's centre, relative to the → real equator and the → real equinox, at a certain date. It includes the displacements from one heliocentric direction, given in a stellar catalogue, due to → precession, → nutation, → aberration, → proper motions, → annual parallax, and light gravitational deviation (M.S.: SDE).

apparent; → position.

apparent rising
  بر‌آیش ِ پدیدار   
barâyeš-e padidâr

Fr.: lever apparent   

The instant of time when the object is in the East and the geometric → zenith distance is equal to 90° plus the → horizontal refraction plus the semidiameter minus the → parallax.

apparent; → rising.

apparent setting
  فروشد ِ پدیدار   
forušod-e padidâr

Fr.: coucher apparent   

The instant of time when the object is in the West and the geometric → zenith distance is equal to 90° plus the → horizontal refraction plus the semidiameter minus the → parallax.

apparent; → setting.

apparent sidereal day
  روز ِ اختری ِ پدیدار   
ruz-e axtari-ye padidâr

Fr.: jour sidéral apparent   

The time interval between two successive → upper transits of the → true equinox of date.

apparent; → sidereal; → day.

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