Astronomical Almanac 2000
Various Definitions (some accurate some are approximations)
Universal time is defined in terms of greenwich mean sidereal time.
Greenwich mean sidereal time (GMST) is defined as the Greenwich hour angle of the mean equinox of date.
Page 1 This page defines sidereal time, then right ascension, declination etc etc and the equation of time
Page 2 This page finalizes with the calculation of rising and setting times.
Also note the following year length definitions from page C1
The lengths of the principal years at 2000.0, as derived from the Sun's mean motion are:
Tropical Year (Equinox to Equinox) = 365.242190 = 365d 05hr 48min 45.2sec
Sidereal Year (Fixed Star to Fixed Star) = 365.256363 = 365d 06hr 09min 09.8sec
Anomalistic Year (Perigee to Perigee) = 365.259635 = 365d 06hr 13min 52.5sec
Eclipse Year (Node to Node) = 346.620075 = 346d 14hr 52min 54.5sec
Also note the day length definitions from page B6
1 Mean Solar Day = 1.00273790935 Mean Sidereal Days = 24hr 03min 56.55537sec
1 Mean Sidereal Day = 0.99726956633 Mean Solar Days = 23hr 56min 04.09053sec
Also note the lengths of mean lunar months from page D2
The lengths of the mean months at 2000.0, as derived from the mean orbital elements are:
Synodic Month (New Moon to New Moon) = 29.530589d = 29d 12hr 44min 02.9sec
Tropical Month (Equinox to Equinox) = 27.321582d = 27d 07hr 43min 04.7sec
Sidereal Month (Fixed Star to Fixed Star) = 27.321662d = 27d 07hr 43min 11.6sec
Anomalistic Month (Perigee to Perigee) = 27.554550d = 27d 13hr 18min 33.1sec
Draconic Month (Node to Node) = 27.212221d = 27d 05hr 05min 35.9sec
If anybody has high accuracy mean planetary periods (to many decimal places) please let me know. I'm particularly interested in the 5 visible planets.