While doing research for my GN. You can plug in dates and see planetary positions from overhead. It really helped me to spot some flaws in the dates I chose for my novel. http://www.solarsystemscope.com/ What was once two years flat travel time from Earth to Jupiter, turned into 2 years, 3 months with the dates of launch and arrival very much adjusted to make sure Earth was in a good position for launching the mission so that Jupiter would be in a good position to receive the mission. It's bookmarked now.
