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Astro*Dictionary by Michael Erlewine

 

 

 

 

2 articles for "Rise"

Rise/Set/Transit [Munkasey M]

An astronomical position where a Body is conjunctthe Horizon in the East.

 

See also:
♦ Cosmical ♦ Rising Planet ♦ Rising Time of a Planet, How to Approxima ♦ Ortive Difference
Rise/Set/Transit [Astro*Index]

During a single day, a celestial body may rise above the Eastern Horizon, set below the Western Horizon, and transit the Upper Meridian and Lower Meridian. See Figure R1. Rising is determined when the upper limb of the body, affected by refraction and parallax, first appears on the Eastern Horizon. Setting is determined when the upper limb of the body, affected by refraction and parallax, last appears on the Western Horizon. Note that this definition leads to somewhat different moments of time than that obtained from computations based on the center of the visible disk (and which ignore refraction and parallax). Transit of the Upper or Lower Meridian is specified by the center of the visible disk (affected by refraction and parallax). Such transits may also be specified by the crossing of a particular limb (west or east) over the meridian. In order for a body to rise, or set, its Declination must be numerically greater than the geographic latitude of the observer; otherwise, the object is circumpolar, never rising or setting.

 

See also:
♦ Celestial Body ♦ Transit ♦ Meridian ♦ Refraction ♦ Limb ♦ Declination ♦ Circumpolar ♦ Geocentric Parallax

 

Astro*Index Copyright © 1997 Michael Erlewine