CELESTIAL MOTIONS

I. Daily Motions (diurnal motions):
• due to the rotation of the Earth on its axis

II. Annual variations:
• due to the orbital motion of the Earth

III. Monthly variations:
• due to the orbital motion of the Moon
• Eclipses

IV. Motions of the planets:

V. Precession:

• due to the interaction between the Earth and Moon

TABLE OF SIGNIFICANT CELESTIAL PERIODS

   Motion               Period

Sidereal day        23 h 56 m 4.091 s
Solar day          >23 h 56 m 4.091 s
Mean Solar day      24 h

Sidereal month      27 d 7 h 43 m 11 s
Synodic month       29 d 12 h 44 m 3 s

Sidereal year       365 d 6 h 9 m 10 s
Tropical year         365 d 5 h 48 m 45 s