History of the National Football League on television
NBC was the first major television network to cover an NFL game, when on October 22, 1939, it broadcast a game between the Philadelphia Eagles and the Brooklyn Dodgers; the network was still only in its infancy, with only two affiliates, the modern day WRGB (now a CBS affiliate) in Schenectady and W2XBS in New York City. Portions of that game still survive via films, but the film is not footage from the telecast (recordings of television broadcasts did not begin until 1948). The use of a sideline camera, the sole camera used in the 1939 broadcast, would become the standard for all future NFL broadcasts until 2017; the angle is particularly suited for estimating yardage, compared to more mobile camera angles that began to appear in the 21st century.
NFL on CBS
On December 22, 1968, CBS interrupted coverage of a Western Conference championship game between the Minnesota Vikings and Baltimore Colts in order to show a broadcast from inside the Apollo 8 spacecraft, headed towards the moon (the first manned space mission to orbit the moon, and a major step towards the lunar landing the following July). The interruption began approximately three minutes before halftime of the game, and lasted 17 minutes. CBS showed highlights of the missed action (in which neither team scored) when the network returned to football coverage; nonetheless, the network received approximately 3,000 complaints after the game.