An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 8 Search : annual
annual
  سالانه   
sâlâné

Fr.: annuel   

Covering the period of a year; occurring or happening every year or once a year.

Annual, from M.Fr. annuel, from L.L. annualis, blend of L. annuus "yearly," from annus "year" and L. annalis "yearly," from annus "year," from PIE *atnos, from *at- "to go" (Skt. a'tati "he goes, wanders").

Sâlâné, from sâl, → year, + âné "-ly".

annual aberration
  بیراهش ِ سالانه   
birâheš-e sâlâné

Fr.: aberration annuelle   

The apparent, small displacement in position of a star during the year due to the → aberration of starlight. It depends on the → celestial latitude, and its maximum value is about 20''.50. See also → constant of aberration; → aberration orbit.

annual; → aberration.

annual apparent motion
  جنبش ِ سالانه‌ی ِ پدیدار   
jonbeš-e sâlâne-ye padidâr

Fr.: mouvement annuel apparent   

annual motion.

annual; → apparent; → motion.

annual equation
  هموگش ِ سالانه   
hamugeš-e sâlâné

Fr.: équation annuelle   

An irregularity in the Moon's orbit, which can amount to 11 degrees in a period of one year. It results from the Sun's disturbing effect on the motion of the Moon due to varying distance between them.

annual; → equation.

annual motion
  جنبش ِ سالانه   
jonbeš-e sâlâné

Fr.: mouvement annuel   

The annual apparent motion of the → Sun in the sky with respect to → fixed stars along the path called → ecliptic. The apparent annual motion is due to the → Earth's → revolution about the Sun. In the course of this motion, the Sun appears to shifts about 1° eastward per day.

annual; → motion.

annual parallax
  دیدگشت ِ سالانه   
didgašt-e sâlâné

Fr.: parallaxe annuelle   

The difference in position of a star as seen from the → Earth and → Sun, i.e. the angle subtended at a star by the mean → radius of the Earth's orbit around the Sun. Same as → heliocentric parallax. Because the Earth revolves around the Sun, we observe the sky from a constantly moving position in space. Therefore, we should expect to see an annual effect, in which the positions of nearby objects appear to oscillate back and forth in response to our motion around the Sun. This does in fact happen, but the distances to even the nearest stars are so great that we need to make careful observations with a telescope to detect it. The annual parallax of the nearest star, → Proxima Centauri, is 0.762 arcsec, which is too small for our → acuity of vision.

annual; → parallax.

annual variation
  ورتش ِ سالانه   
varteš-e sâlâné

Fr.: variation annuelle   

Generally, the variation of a quantity over a year. In particular the yearly change in the right ascension or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star.

annual; → variation.

constant of annual aberration
  پایا‌ی ِ بیراهش سالانه   
pâyâ-ye birâheš sâlâné

Fr.: constante d'aberration annuelle   

Same as → constant of aberration.

constant; → annual; → aberration.