Originally a sci-fi series in the 70's trying to cash in on Star Wars, it was remade in 2003 with a slightly more dramatic vision. Below are the complete listing of products for both versions of the show and their respective order.
In 2003 the remake started with a miniseries. The success of the miniseries lead to a pickup for a full pilot season of 13 episodes. Since then it has continued on and has 4 seasons and 2 telemovies in its canon.
Season 4: Part 1
Season 4: Part 2