Astronomy is the most ancient science, no doubt studied by people to keep track of the seasons so that the right time was known for hunting and planting and other activities. So it was closely linked to the seasons and weather and climate from the start.
Stonehenge is approaching 5,000 years old and was initially a means to study the motion of Sun and moon and how the configurations changed through the seasons and with longer cycles connected with the lunar orbital motions. By 3,700 years ago ancient Britons had such precise knowledge of the periods of lunar and solar configurations that they could predict eclipses far ahead.
Knowledge of the 19 year eclipse cycle know as the Metonic cycle was actually taken to Greece from Britain according to Sir Fred Hoyle, and from there came down to modern times. Hoyle also mentions that stonehenge keeps track of three motions, the Sun, the moon and the node of the moon's orbit. All three must come together to have an eclipse. It seems that the idea of a holy trinity may have started with these three "Gods", the node being the invisible holy spirit.
The details of lunar orbital motion are quite complex and dealt with in a special lunar section. There are also Saros eclipse cycle calculations by Fred Espenak. It is common knowledge that the moon and Sun are responsible for tides in the sea, but atmospheric tides are equally important as they strongly affect weather conditions. These variations in the lunar orbit have periods of 18.6 and 8.85 years and interact in 6.0 years. Cycles of these periods and half these periods, because tides happen twice per cycle, are all commonly reported cycles.
Of course astronomy is full of periodicities or cycles. The rotation of the earth, the revolution of the earth around the Sun, the revolution of the moon around the earth, all the other planets and moons rotation and revolution periods are just the start. There are also synodic periods for conjunctions, the sunspot cycle, and our motion around the galaxy and up and down through the plane of the galaxy.
Milankovitch suggested that three motions of the earth's orbit and axis were responsible for the periodicities found in ice ages. Recently it has been suggested that he had this slightly wrong, but that orbital periods are still responsible.
In summary then, astronomical motions and variations are responsible for the many time periods that we keep as well as seasonal, weather and climatic changes. Other areas of cycles in astronomy are variable stars, binary stars, pulsars, galactic cores, solar oscillations and perhaps the oscillation of the entire universe.
Cycles in time are closely connected to periodicities in space because the wave nature of all forces automatically causes periods to produce spacings and vice versa. It is accepted that nucleons (protons and neutrons) sit at distances which are related to their wavelength's which are dependant on their Compton frequencies. Likewise, atoms in crystals are at regular distance spacings.
Bode's law of planetary distances sits somewhere between sense and curiosity, but with a little modification it is also seen to be connected with regular oscillations also. This realisation can help us towards a greater understanding of the wave nature of the universe and the presence of cycles in everything.
It is less well known that galaxies also have periodicities of distance, but this has been clearly demostrated by many papers of William Tifft, Halton Arp and others. In the last decade even larger scale regular spacings of galactic clusters and superclusters have been reliably reported. Big bang cosmology cannot deal with these facts, and so many astronomers and cosmologists keep on pretending that these facts have not been observed.
Even stellar distances show periodicities, and in a fascinating connection to the work of Dewey we find that the distance periodicities in light years match commonly reported cycles in years. This clearly demonstrates that there is a wave structure present and that the waves have the velocity of light to make this correspondence. The same situation applies to the galactic cluster waves which have spacings that match with geological cycle periods. Clearly the universe consists of vast waves sloshing about and being responsible for both regular structures in space and cycles in time.
The periodicities in the distances of the stars is very similar to atomic bonds. Likewise with galaxies, and in a way the milky way and andromeda galaxies may be seen as giant H2O molecules, each with their one large galaxy similar to oxygen atoms and two hangers on like the much smaller hydrogen atoms. In this case the bond length is 180,000 light years.
It is not possible, when considering astronomy from a cyclic point of view to not consider its relationship to astrology. It is a constant point of irritation with astronomers that the public confuse the two. It is even more embarassing that so many famous astronomers practiced astrology, although this is generally dismissed as being a necessity of livelihood. However reluctant one may be, the serious student of cycles finds that the periods of astronomical configurations keep on appearing in many things studied on earth and that something is going on.
Dewey resisted the apparent connection for as long as he could, but eventually the evidence became so great that he admitted it. The problem is that so much nonsense has been practiced by charlatans in the name of astrology, and so much of the lore is just plain wrong, that it is very difficult to steer a middle path between acceptance and rejection. However the correct approach is to look at all proper scientific research and to ignore the bunk. When this is done, it is found that a study of cycles and wave structures can help to scientifically explain the observed connections between the cosmos and events on earth.
Planetary Orbits and Calculations
The serious student of cycles who is interested in planetary effects will want to be able to calculate the positions of the planets and moon at any time. Some resources that will help with this are:
Paul Schlyter of Stockholm, Sweden explains
How to compute planetary positions and
Computing planetary positions - a tutorial with worked examples which will allow moderately accurate positions suitable for most purposes.
For those that want to know how Pierre Simon Laplace dealt with the issue of planetary and lunar motion, his five volume Mécanique céleste was translated into English as the The Mary Somerville Project (Mechanism of the Heavens Etext). This is a very substantial treatment for the experts.
Saros eclipse cycle calculations by Fred Espenak.