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: 2 Search : proper motion
proper motion
  جنبش ِ سره   
jonbeš-e saré

Fr.: mouvement propre   

The apparent motion of a star across the sky (not including a star's parallax), arising from the star's velocity through space with respect to the Sun. Proper motion is usually tabulated in star catalogs as changes in right ascension and declination per year or century. See also: → proper motion distance.

proper; → motion.

proper motion distance
  دورای ِ جنبش ِ سره   
durâ-ye jonbeš-e saré

Fr.: distance mouvement propre   

The distance derived from the → proper motion of an object. If an object has a known → transverse velocity  u, and has an observed angular motion of dθ/dt, then the proper motion distance is defined as: d = u/(dθ/dt).

proper; → motion; → distance