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| the time when the sun is farthest south from the celestial equator occurring around December 21st |
| a zodiacal constellation between Leo and Libra, containing the bright star Spica also called the Virgin |
| hour circle | |
| —n | |
| a great circle on the celestial sphere passing through the celestial poles and a specified point, such as a star | |
| hour circle
A great circle passing through the poles of the celestial sphere and intersecting the celestial equator at right angles. An hour circle is equivalent to a meridian on Earth and is used in describing the position of a celestial body with respect to an observer's celestial meridian. See more at hour angle. |
hour circle
in astronomy, any great circle (similar to longitude) on the celestial sphere that passes through the celestial poles-i.e., is perpendicular to the celestial equator. The declination of a celestial object is measured along its hour circle. The hour circle that at any moment is passing through an observer's zenith is his meridian.
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