  Over 30 years of solar data have been acquired by the Birmingham Solar
Oscillations Network (BiSON), an international network of telescopes used to
study oscillations of the Sun. Five of the six BiSON telescopes are located at
major observatories. The observational sites are, in order of increasing
longitude: Mount Wilson (Hale) Observatory (MWO), California, USA; Las Campanas
Observatory (LCO), Chile; Observatorio del Teide, Iza\~{n}a, Tenerife, Canary
Islands; the South African Astronomical Observatory (SAAO), Sutherland, South
Africa; Carnarvon, Western Australia; and the Paul Wild Observatory, Narrabri,
New South Wales, Australia. The BiSON data may be used to measure atmospheric
extinction coefficients in the $\mathrm{I_c}$ band (approximately 700-900 nm),
and presented here are the derived atmospheric extinction coefficients from
each site over the years 1984 to 2016.
