.. a star shone. Lots of them, in fact. And somewhat more recently, some people have made it their career to look at them. That's not a bad choice, if you can hack the math. However, as science has progressed, the number of sites where cutting-edge research can be done has shrunk, especially at the optical wavelength. Because the Earth's atmosphere is opaque to much of the electromagnetic spectrum, including light to some degree, telescopes are best located at high-elevation sites. A site should also be dry, have stable air, and be upwind from large land masses so that the amount of aerosols is lower. And finally, a site should not have a lot of light pollution. Those factors limit the number of premier sites for optical astronomy to three, which are northern Chile, the island of La Palma in the Atlantic, and the islands of Hawai'i and Maui in the Pacific. Southern California would be included in that list, but the megalopolis of LOSSAN gives off too much light pollution. So the best sites in the US are farther from the coast, in Arizona and New Mexico. Western Morocco, Namibia, and Baja California are being looked at for potential locations by more observatories as other good sites fill up, but for now they remain mostly undeveloped.
All that is by of way introducing my latest maps, which are of major astronomical observatories in North America and in South America. Both maps contain all of the "research-class" telescopes that I have found on the net. Included are all optical (which includes near-UV and infrared) telescopes over 1.0m (40"), many optical telescopes down to about 0.4m depending on location, a number of project-dedicated optical telescopes, most solar telescopes, and most radio telescopes. Not included are telescopes primarily used for teaching, historic telescopes, telescopes at science museums and planetariums, telescopes used by amateurs for minor planet discovery, and indirect observing projects such as neutrino and cosmic ray observatories. There's nothing wrong with those instruments, or their purposes. But either they aren't used for research that will contribute to the body of astronomical knowledge, or they can't image distinct sources. As always, I have tried to be as thorough as possible, but there are certainly a few inaccuracies. And since I don't speak Spanish or Portuguese, the South American map is undoubtedly incomplete.