OK, I've said before that I worked on the Keck Telescope (see this post). I love seeing what is still a favorite project of my professional life. Those 36 (now 72) mirrors were the result of a ton of great engineering and a lot of painstaking work. I'm proud to have been part of it.
Keep an eye out for all the maintenance required to keep the telescope operating at its peak. Also, remember that even though Keck is located at arguably the best place on the planet for an optical telescope, it still only operates at its absolute best for one day a year. The conditions have to be just right.