Mount Wilson, California, USA
This instrument was installed in 1992, and uses a small fraction of the beam from the 60-foot solar tower (shown above). It was initially installed on Haleakala in Hawaii (1981), where it operated until 1991. This picture was taken from the 150-foot solar tower.
Las Campanas, Chile
Las Campanas was commissioned in 1991. It is equatorially mounted and housed in a small dome. This site consistently produces the best BiSON data.
Sutherland, South Africa
The instrument is installed in a dome situated at the South African Astronomical Observatory (SAAO), at Sutherland, Cape Province. It was commissioned in, and has been producing data since 1990.
Izaña is the longest-running site of BiSON and has been producing data since 1975. Our station is situated at the Observatorio del Teide (in the pyramid-like building). It is operated under a collaboration with the I.A.C., and requires daily attention.
Unlike the more recent stations, this spectrometer is not equatorially mounted. Sunlight is fed into the instrument using a coelostat (shown in the above image) - an arrangement of mirrors which change their orientations during the day to follow the course of the Sun. The output beam is then reflected through a hole in the wall of the pyramid into the instrument.
Carnarvon, Western Australia
Carnarvon was the third BiSON site and was the first to have a spectrometer equatorially mounted in a dome. It was commissioned in 1985.
The site is situated close to sea level, near to the Indian Ocean. The other buildings in the picture above are the relics of the old Carnarvon satellite tracking station.
Narrabri, New South Wales, Australia
Narrabri was commisioned in 1992 - the instrument is equatorially mounted and housed in a small dome. The station is situated within the grounds of the ATNF’s Paul Wild Observatory.