Astro*Dictionary by Michael Erlewine
5 articles for "Circle"
Circle [DeVore]The complete circle of the zodiac, or 360 degrees of 60 minutes each.
See also:Circle of Equal Altitude [Astro*Index]
♦ Astronomy ♦ Zodiac
A small circle, on the celestial sphere, which is everywhere equidistant from the Horizon.
See also:Circle of Equal Altitude [Munkasey M.]
♦ Almucantar ♦ Small Circle ♦ Celestial Sphere
A circle which is everywhere equidistant from a pole.
See also:Circle of Position [Astro*Index]
♦ Almucantar ♦ Small Circle ♦ Celestial Sphere
A circle of equal zenith distance; equivalent to an almucantar. Two or more intersecting circles of position are used by navigators to specify position at sea.
See also:Circle of Position [DeVore]
♦ Zenith Distance ♦ Almucantar
Circles intersecting the horizon and meridian, and passing through a star: in terms of which to express the position of the star. Their use is now obsolete. However, Circles of Position were not so used by Ptolemy or Placidus, who measured the distance of every star by its semi-arc.
See also:
♦ Zenith Distance ♦ Almucantar
Astro*Index Copyright © 1997 Michael Erlewine
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