English: The National Solar Observatory facilities loom large in the foreground of this aerial view, overshadowed by the diagonal shaft and vertical pier support of the McMath-Pierce solar facility. To the right is the tower of the SOLIS facility, showing two of its three lightning protection poles. The square building in the middle houses the Fourier Transform Spectrograph facility, used with the McMath-Pierce but also for laboratory experiments in infrared spectroscopy. The small dome in front houses the Crossley monitoring telescope, which feeds a continuous hydrogen-alpha image of the full disk of the Sun into the rest of the facility for monitoring convenience. In the background, the ridge is, as always, dominated by the Mayall 4-meter telescope.