
The way up is the Angeles Crest Highway, narrow and full of hairpins, about 45 minutes from Pasadena. Check that the road and the observatory are open before you go, especially in winter.
Mount Wilson Observatory has sat atop the San Gabriels since 1904, when George Ellery Hale built what became one of the most important telescope sites in the history of astronomy. For drivers it's the payoff at the top of one of Southern California's great roads, reached up the Angeles Crest Highway at over 5,000 feet.