Big Bear Solar Observatory

A observatory located at an altitude of 2,000 metres (6,600 feet) on an island in Big Bear Lake in California. The site was chosen to eliminate the distortion caused by turbulence over land heated by the Sun. Formerly owned and operated by the California Institute of Technology, it was transferred in 1997 to the New Jersey Institute of Technology. There are three main telescopes on the same mount: a 65-centimetre (26-inch) reflector, a 25-cm (10-inch) refractor and a 15-cm (6-inch) refractor. The smallest telescope is used to monitor the whole Sun. The 25-cm is equipped with a magnetograph, and there is a spectrograph fed by light from the 65-cm. An additional instrument is dedicated to the study of helioseismology.