時じ圏けん

noun

hour circle; circle of declination

Technical term in astronomy; refers to a great circle on the celestial sphere passing through the celestial poles and a given point, used in equatorial coordinate systems.

• 時じ圏けんは天てん球きゅう上じょうの大だい円えんで、天てんの極きょくと天てん体たいを通とおる。

  The hour circle is a great circle on the celestial sphere that passes through the celestial poles and a celestial body.