Telescopes outfitted with modern electronic cameras and spectrographs are astronomers' primary tools for exploring the Universe. In this lecture I review the primary types of telescopes and the best observatory sites to locate them, with a brief mention of radio and space telescopes. At the end, I give a brief review of the Ohio State's observing facilities. Recorded 2007 Oct 26 in 1000 McPherson Lab on the Columbus campus of The Ohio State University.