The Muon Detector is of course not used solely for finding the arches and is most often used for finding the other easter eggs on the MÃ¼n, Kearth, and Minmus. I haven\'t spent a lot of time looking for the ones on Kearth, though that\'s next. I\'ve just about covered everything I can on the MÃ¼n. 1st: 2.424 North / 81.444 East 2nd: 12.471 North / 39.261 East 3rd: 12.454 South / 140.826 West (750 meters underground from my best calculations) You should really try to find them yourself before resorting to just being told though, it\'s much more fun Niftyâ€¦ thanks for the link to the Muon detector. Also, it\'s Kerbin, not Kearth.