Big Bear Solar Observatory, on Big Bear Lake in Southern California’s San Bernardino Mountains, is a specialized solar research facility operated by the New Jersey Institute of Technology. Its lake setting and high elevation provide unusually steady daytime air, making it especially well suited for studying the Sun. The observatory began with several smaller telescopes and later developed its most important modern instrument, the 1.6-meter Goode Solar Telescope, which achieved major advances in adaptive optics and highly detailed solar observation. Until 2019, it was the world’s largest clear-aperture solar telescope. The observatory’s administration shifted from Caltech to NJIT in the late 1990s.