This animation illustrates the motion of [url=http://en.wikipedia.org/wiki/Jupiter]Jupiter[/url] and [url=http://en.wikipedia.org/wiki/Saturn]Saturn[/url] in a geo-centric model to explain the occurance of their conjunctions. [br][br]These [url=http://en.wikipedia.org/wiki/Astronomical_conjunction]conjunction[/url]s (called the [url=http://en.wikipedia.org/wiki/Great_conjunction]Great Conjunction[/url]s) occur approximately once every 20 years, in different segments of the Zodiac. They return to the same segment of the Zodiac approximately every sixty years thus setting up a 60-Year cycle. When returning, they are further shifted by approximately 8 degrees thus resulting in these conjunctions drifting across the entire zodiac over time.[br][br]In the graphic below, you can play with the [i]60-Year Cycle[/i] and [i]Conjunction[/i] sliders to position the planets at a set of pre-calculated conjunctions.[br][list][br][*]The 60-Year Cycle slider illustrates the 8 degree drift of a conjunction.[br][*]The Conjunction slider illustrates the three conjunctions that happen in one 60 year cycle.[br][/list][br][br]For a detailed exposition of the Great Conjunction, refer [url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?2000JRASC..94..174E&classic=YES]Conjunctions of Jupiter and Saturn[/url], Donald E. Vetz, Journal of the Royal Astronomical Society of Canada, 2000 Aug./Oct.