Difference between revisions of "Apparent solar day"

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<div class="definition"><div class="short_definition">(<br/>''Also called'' true solar day.) The interval of time between two successive transits  of the sun across a [[meridian]].</div><br/> <div class="paragraph">This interval is about four minutes longer than the sidereal day, largely because of the sun's  apparent annual motion eastward along the [[ecliptic]] (actually, the earth's &ldquo;westward&rdquo; motion along  its [[orbit]]), which motion delays the sun's return to [[meridional]] transit. Also, this interval is inconveniently  nonuniform due to systematic variations in the earth's orbital speed around the sun  and the sun's changing [[declination]]. The concept of the [[mean solar day]] has been invented to  circumvent these practical difficulties.</div><br/> </div>
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<div class="definition"><div class="short_definition">(''Also called'' true solar day.) The interval of time between two successive transits  of the sun across a [[meridian]].</div><br/> <div class="paragraph">This interval is about four minutes longer than the sidereal day, largely because of the sun's  apparent annual motion eastward along the [[ecliptic]] (actually, the earth's "westward" motion along  its [[orbit]]), which motion delays the sun's return to [[meridional]] transit. Also, this interval is inconveniently  nonuniform due to systematic variations in the earth's orbital speed around the sun  and the sun's changing [[declination]]. The concept of the [[mean solar day]] has been invented to  circumvent these practical difficulties.</div><br/> </div>
 
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Latest revision as of 14:39, 20 February 2012



apparent solar day

(Also called true solar day.) The interval of time between two successive transits of the sun across a meridian.

This interval is about four minutes longer than the sidereal day, largely because of the sun's apparent annual motion eastward along the ecliptic (actually, the earth's "westward" motion along its orbit), which motion delays the sun's return to meridional transit. Also, this interval is inconveniently nonuniform due to systematic variations in the earth's orbital speed around the sun and the sun's changing declination. The concept of the mean solar day has been invented to circumvent these practical difficulties.


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