Star Trek
Star Trek is probably the most popular ever science fiction series of all time (although the Star Wars movies were probably more popular).
The original series aired in the 1960s and was not particularly long-running. However, they then made movies based on the original series, which then made the original series more popular. In the 1980s, 1990s and 2000s, various spin off shows were created, including Star Trek: The Next Generation, Star Trek: Deep Space 9 and a wide variety of other spin off shows, based loosely on the Star Trek universe. Other shows such as Babylon 5 were loosely based on the Star Trek universe but had no explicit crossovers with the original series.
Star Trek is regarded by many as true science fiction because they are incredibly consistent. Many of the things that they present are theoretically possible and may come true one day. Other things, whilst theoretically impossible, are nonetheless consistently presented in the Star Trek universe.
Fans of Star Trek delight in finding the holes in the series because the holes are so difficult to find. Only the true fans are able to find true inconsistencies that cannot be explained away.