On a clear day you, too, can see the mountains of Altadena. I stumbled upon this website while contemplating a motorcycle ride with my husband up to the Mount Wilson Observatory just a few miles into the mountains north of my home in Altadena.
The camera changes pictures every 2 minutes on the site http://www.astro.ucla.edu/~obs/towercam.htm When you visit the site you can find out all about the history of the Mt. Wilson Observatory, see current satellite images of Southern California, and go to links of other observatories http://physics1.usc.edu/solar/links.html
Here's a map borrowed from their website ... and if you're wondering where Altadena is, it's just North of Pasadena and just East of La Canada Flintridge and 15 minutes north of downtown Los Angeles.