OMNI magazine cover
OMNI was a magazine that discussed scientific topics in the 20th century.
A passenger on a bus that James T. Kirk and Spock rode on when they traveled back to 1986 was reading an issue of OMNI. (Star Trek IV: The Voyage Home)
The copy that appeared in the film was the May 1986 edition; the cover reads: "Special Souvenir Edition, OMNI, 25th Anniversary of American Manned Spaceflight". It featured a photograph of astronaut Harrison Schmitt during the 1972 Apollo 17 mission.
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