When a star reaches the meridian in its course across the celestial sphere it is said to culminate or reach its culmination.
The earth, argued Ptolemy, lies at the centre of the celestial sphere.
The zodiac is the part of the celestial sphere which lies about eight degrees on each side of the ecliptic.
It was only the northern half of the celestial sphere which had been fully explored.
The celestial equator is the great circle in which the plane of the earth's equator intersects the celestial sphere.
A star rising due east would traverse this great circle of the celestial sphere and set due west.
Does it occur because the Soul is within the celestial sphere, which tends to revolve about her?
This corresponds to the Tropic of Cancer on the celestial sphere, which marks the greatest northern declination of the sun.
One of them was a celestial sphere eight feet in diameter, containing all the stars known in 1650 and visible in Pekin.
In Fig. 5, the outer arc again represents the path of the zodiac on the celestial sphere.
celestial sphere |
An imaginary sphere with Earth at its center. The stars, planets, Sun, Moon, and other celestial bodies appear to be located on this sphere, and the sphere appears to rotate around the Earth's extended axis once every 24 hours, carrying the celestial bodies with it overhead and giving them their diurnal motions. The celestial sphere is essentially a spherical map of the sky that provides the basis for the coordinate systems used in celestial navigation and in specifying the positions and motions of celestial objects. See more at altazimuth coordinate system, ecliptic coordinate system, equatorial coordinate system.