Sizing Up Space
Distances in space are difficult to grasp. We really can't comprehend distances much beyond the orbit of Pluto, so how can we wrap our heads around galaxies that are billions of light years away?
Sizing Up Space is an introduction to distances in the universe, all based on the time it takes light to travel (186,000 miles per second).
A nice introduction to the program Big or as an add-on to any planetarium program.