COSMOS starts its run tonight, on 10 different networks in the United States. Outside the U.S. I would seek it out on channels affiliated with the FOX or National Geographic networks. If you manage to miss it tonight, each episode will be repeated a couple of times during the week. Presumably there will be the downloads, and the DVDs, and other alternative viewing methods. There are 13 episodes, so you can schedule your next few months accordingly.
It’s been an impressive public relations campaign, perhaps topped off by having President Obama introduce the series tonight. Ratings will be just one indicator of how well the program comes across. The right people are involved Besides the near-ubiquitous host Neil deGrasse Tyson, writers from the first COSMOS are involved, as well as television producers Seth MacFarlane (whose programs usually air during the COSMOS timeslot) and Brannon Braga (who cut his teeth on the Star Trek spinoffs).
In other science non-fiction programming, Particle Fever is in festival release as of this weekend. As of this Friday, it will be available in a few more theaters, and appears to be rolling out slowly over the spring. The film documents the work at the Large Hadron Collider to find the Higgs Boson. The reviews have been strong, but check out this trailer to see if it appeals to you.