Daniel Jackson to visit SGA!! (from tv.com):
90. First Contact (1)
First aired: 9/26/2008 Production Code: 510
Daniel Jackson visits Atlantis to do some research on the Ancient scientist Janus.
Writer: Martin Gero
Director: Andy Mikita
Guest star: David Nykl (Dr. Radek Zelenka), Mitch Pileggi (Colonel Steven Caldwell) , Michael Shanks (Dr. Daniel Jackson)
http://www.tv.com/stargate-atlantis/show/11415/episode_guide.html?season=5&tag=season_dropdown;dropdown;4 (http://www.tv.com/stargate-atlantis/show/11415/episode_guide.html?season=5&tag=season_dropdown;dropdown;4)