Satellite orbits consist of two parts: the apogee--the object's highest point in relation to earth, and the perigee, its lowest.
For many people the low point of the 1980s was "Black Monday", the October 19th, 1987 stock market crash, in which the Dow lost 508.32 points to end at 1,738.40 (as of the day I'm writing this, it's currently at 10,836.53, just to put things in perspective).
But I'd be willing to make the case that in terms of pop culture, the apogee, the acme, the zenith, (so to speak) of the 1980s came two years earlier: the second season of Miami Vice, which debuted in September of 1985 and was just released on DVD.
The first season of Vice had gotten so-so ratings, taking off slowly. But by the summer, it began to gather steam, even putting stars Don Johnson and Philip Michael Thomas on the cover of Time magazine.
But when the second season debuted with an episode called "The Prodigal Son", everything exploded. Never again would a single television show dominate pop culture in the same way that Vice did that year--even though the show ran at 10:00 PM on Fridays, once a time slot where television shows went to die (Star Trek was banished there by NBC during its not-coincidentally last season in 1969). And no other show more personified the look and feel of the 1980s than Vice. (In retrospect, it seems like you could catch all sorts of moments of eighties zeitgeist from the show, moments when one trend died and another began. As James Lileks once wrote, "Here's a pivotal moment in American culture: the moment Sonny Crockett no longer smoked Luckies"--actually no longer smoked anything at all, as Johnson quit smoking near the end of the second season.)
During the second season, the Miami Vice theme song hit number one on the charts--the last time a TV theme did that was Henry Mancini's Peter Gunn theme. Vice composer Jan Hammer (whom I interviewed for Blogcritics in 2003) said that Mancini called to congratulate his success when the Billboard charts hit the streets.