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Ecliptic
The sun's mean path on the celestial sphere. It is inclined by
approximately 23.4° relative to the celestial equator. The ecliptic pass
points in the first days of the months are displayed on the 24-hour dial.
Vernal equinoctial
point
Of the two intersections between the ecliptic and the celestial equator,
this is the point that the sun passes through as it moves from the south
side of the celestial equator to the north side. The other intersection is
the autumnal equinoctial point. The vernal equinox and the autumnal
equinox occur when the center of the sun passes through these points.
Declination and
right ascension
Declination and right ascension determined by using the celestial
equator and the vernal equinoctial point as a standard in order to
describe positions on the celestial sphere. The declination is 0° on
the celestial equator, and it is measured as far as +90° north of the
celestial equator (celestial north pole) and -90° south (celestial south
pole). The right ascension is 0° above the vernal equinoctial point, and
it is measured as it turns to the east as far as 359° 59' 59".9… Usually,
instead of degrees, minutes and seconds, the value for right ascension is
converted to 0h - 23h 59m 59.9…s with 15° = 1 hour.
Summary of Contents for CAN18
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