This is a really cool simulation that shows the relationship between Mars and Earth's orbital motion while simultaneuosly showing Mars' changes in size. Also illustrates how it only comes into opposition every two years even though the Earth goes around once a year. Check 2003-2005, 1999-2001, 1986-1988 etc. (15-17 yr cycle). http://www.windows.ucar.edu/tour/link=/mars/mars_orbit.html&edu=high Jack Jones Public Events Coordinator Saguaro Astronomy Club Phoenix AZ Telescoper@xxxxxxx www.saguaroastro.org -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.