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: 6 Search : diurnal
constant of diurnal aberration
  پایا‌ی ِ بیراهش روزانه   
pâyâ-ye birâheš ruzâné

Fr.: constante d'aberration diurne   

The quantity 0''.3200 ρ cos φ', where ρ is the geocentric distance of the observer measured in units of → equatorial radius the Earth and φ' is the observer's → geocentric latitude. The numerical part is equal to 2πa csc1'' / (cP), where a is the equatorial radius of the Earth, P is its → sidereal period of rotation, and c is the → speed of light in vacuum.

constant; → diurnal; → aberration.

diurnal
  روزانه   
ruzâné (#)

Fr.: diurne   

Having a period of, occurring in, or related to a → day.

L.L. diurnalis, from V.L. diurnum "day" (Fr. jour), from L. diurnus "daily," from dies "day" + -urnus, an adj. suffix denoting time. Dies "day" from PIE base *dyeu- "to shine;" cf. Gk. delos "clear;" L. deus; Skt. deva "god;" Mod.Pers. div "devil, demon;" O.Pers. daiva- "evil god, demon;" Av. daēva- "evil spirit, false god;" Gk. Zeus "supreme god."

Ruzâné, from ruzday + -âné a suffix forming adverbs and adjectives.

diurnal aberration
  بیراهش ِ روزانه   
birâheš-e ruzâné

Fr.: aberration diurne   

The aberration of a star's position due to the rotation of the Earth. Its value depends on the latitude of the observer, and is only 0''.32 in the case of an observer at the equator, where the rotational velocity is greatest.

diurnal; → aberration.

diurnal circle
  پرهون ِ روزانه، دایره‌ی ِ ~   
parhun-e ruzâné, dâyere-ye ~

Fr.: cercle diurne   

The apparent path of an object in the sky during one day, due to Earth's rotation.

diurnal; → circle.

diurnal motion
  جنبش ِ روزانه   
jonbeš-e ruzâné

Fr.: mouvement diurne   

The daily apparent motion of all celestial objects, due to Earth's rotation.

diurnal; → motion.

diurnal parallax
  دیدگشت ِ روزانه   
didgašt-e ruzâné

Fr.: parallaxe diurne   

The apparent difference between the position of a celestial object measured from the Earth's surface and the position that would be recorded by a hypothetical observer at the center of the Earth. Same as → geocentric parallax.

diurnal; → parallax.