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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 929
apochromatize
  اپافامیدن، اپافام کردن   
apâfâmidan, apâfâm kardan

Fr.: apochromatiser   

To bring the wavelengths of the spatially separate colors to a common focus.

apochromat; → -ize.

apocynthion
  اپامه، اپاماه   
apâmah, apâmâh

Fr.: apolune   

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

Apocynthion, from → apo- "away from, off" + cynthion, from Gk. Cynthia "goddess of the Moon."

Apâmah, apâmâh, from apâ, → apo-, + mah, mâh, → Moon.

apodization
  پازدایی   
pâzodâyi

Fr.: apodisation   

1) Generally, any process suppressing the secondary maxima of a diffraction pattern, such as the faint rings around the Airy disk of an optical image. This allows the telescope to resolve finer details.
2) Over a telescope aperture, the use of a screen that progressively cuts down, from the center to the edge of the aperture, the amount of light transmitted, in order to reduce diffraction.
3) A mathematical treatment carried out on data received from an interferometer before the Fourier transformation is calculated to obtain the spectrum.

Apodization from v. apodize, → a- "negation prefix" + pod from Gk. podos "foot" (compare with Pers. , see below) + -tion "noun forming suffix;" literally "removing feet," i.e. suppressing the secondary maxima at the side of the Airy spot.

Pâzodâyi "removing feet," from "foot," Mid.Pers. pâd, pây , Av. pad-, Skt. pat, Gk. pos, gen. podos, L. pes, gen. pedis, PIE *pod-/*ped-. Zodâyi, n. from zodudan "to polish, clean," Mid.Pers. uzdâtan, Av. uzdâ-, from uz-, → ex-, + dâ- "make, create."

apofocus
  اپاکانون   
apâkânun

Fr.: apocentre   

The point on an elliptic orbit at the greatest distance from the principal focus. Also knwon as → apocenter.

From → apo- "away from, off," + → focus.

From apâ-, → apo-, + kânunfocus.

apogalactic
  اپاکهکشانی   
apâkahkašâni

Fr.: apogalactique   

Of or pertaining to an → apogalacticon.

apo-; → galactic.

apogalacticon
  اپاکهکشان   
apâkahkašân

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.

apogee
  اپازم   
apâzam

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.

apojove
  اپاهرمز   
apâhormoz

Fr.: apojove   

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

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.

apolune
  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.

apparatus
  دستگاه   
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".

apparent
  پدیدار   
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.

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