Motion of the Sun
* The Sun also appears to rise in the east and set in the west
due to the Earth's rotation.
* However, the Sun moves relative to the stars:
* The Sun moves eastward relative to the stars by about 1°
per day.
* The Sun oscillates north/south (within 23°.5 of the celestial
equator) over a period of one year.
* The ecliptic is the Sun's path among the stars.
* It is simply the projection of the Earth's orbital plane onto
the celestial sphere.
Diurnal Path of the Sun
* The Sun's diurnal path varies during the year.
* Time above horizon depends on where it is relative to the celestial
equator.
* Equinoxes occur when the Sun crosses the equator
(about 21 March and 21 September).
* Days and nights have equal length, exactly
12 hours.
* Dates known as the solstices occur when Sun is
farthest from the celestial equator. Summer solstice occurs around
21 June in the northern hemisphere, and winter solstice occurs
around 21 December.
The Zodiac
* The Sun's motion on the ecliptic carries it through a group of constellations called the zodiac.