Twenty-five years ago, the Omni Theater opened at the Museum of Science and became a sensation. The screen was huge and round. The sound system was like nothing on earth. And it featured an iconic opening video of local shots, and a narration from Leonard Nimoy. Through it all, one man, Joe Rivers, has been there, the head of the AV department who actually shot the famous opening. The Omni Theater is his baby, and his baby is aging well.