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: 7 Search : sidereal time
apparent sidereal time
  زمان ِ اختری ِ پدیدار   
zamân-e axtari-ye padidâr

Fr.: temps sidéral apparent   

The → mean sidereal time corrected for the → nutation and shift in the obliquity of the ecliptic that occurs as a result of the Moon's gravitational effect. Apparent sidereal time differs from mean sidereal time in that the → true vernal equinox point is used.

apparent; → sidereal; → time.

Greenwich Apparent Sidereal Time (GAST)
  زمان ِ اختری ِ پدیدار ِ گرینویچ   
zamân-e axtari-ye padidâr-e Greenwich

Fr.: temps sidéral apparent de Greenwich   

The → Greenwich Mean Sidereal Time corrected for → nutation. Therefore, it is measured with respect to the → true vernal equinox. GAST and GMST differ by the → equation of the equinoxes.

Greenwich Meridian; → apparent; → sidereal; → time.

Greenwich Mean Sidereal Time (GMST)
  زمان ِ اختری ِ میانگین ِ گرینویچ   
zamân-e axtari-ye miyângin-e Greenwich

Fr.: temps sidéral moyen de Greenwich   

The → sidereal time related to the angle between the → prime meridian and the → mean vernal equinox, measured in the plane of the equator.

mean; → Greenwich Meridian; → sidereal; → time.

local sidereal time
  زمان ِ اختری ِ محلی   
zamân-e axtari-ye mahali

Fr.: temps sidéral local   

Local time measured by the apparent motion of the stars. It is the most useful form of sidereal time since it gives the right ascension of a transiting celestial object at a given location.

local; → sidereal; → time.

mean sidereal time
  زمان ِ اختری ِ میانگین   
zamân-e axtari-ye miyângin (#)

Fr.: temps sidéral moyen   

The hour angle of the mean equinox for a given observer.

mean; → sidereal; → time.

sidereal time
  زمان ِ اختری   
zamân-e axtari (#)

Fr.: temps sidéral   

The time based upon → Earth's rotation with respect to the stars, with the → sidereal day as the unit of measurement. At the moment when the → vernal equinox crosses the → meridian in → upper culmination, sidereal time is equal to zero hours for that observing position. The → hour angle of the vernal equinox is equal to sidereal time.

sidereal; → time.

true sidereal time
  زمان ِ اختری ِ راستین   
zamân-e axtari-ye râstin

Fr.: temps sidéral vrai   

The → sidereal time with respect to the → true equinox.

true; → sidereal; → time.