Atmospheric Extinction Coefficients in the I_c Band for Several Major International Observatories: Results from the BiSON Telescopes, 1984–2016

The next generation Birmingham Solar Oscillations Network (BiSON) spectrophotometer: a new miniaturized instrument for helioseismology

“…At 770 nm atmospheric extinction is dominated by the contribution of aerosols. The aerosol optical depth at the BiSON site at Las Campanas, Chile, is typically 0.03 magnitudes per airmass, whereas the BiSON site at Izaña, Tenerife, can reach as high as 0.5 magnitudes per airmass during periods of high Saharan dust (Hale et al 2017). At one airmass with an aerosol optical depth of 0.03, the power spectral density at sea level near 770 nm is 1.18 W m −2 nm −1 .…”

“…It is useful to monitor the light that is not scattered by the cell and is transmitted directly through the spectrophotometer. This measurement allows the quality of beam polarisation to be monitored, and also to estimate the daily atmospheric extinction coefficient (Hale et al 2017). Lens L4 is a 50 mm focal length bi-convex lens positioned to focus light exiting from the cell into an image on the transmission detector, via a fixed linear polariser and quarter-wave plate.…”

Measurement of Atmospheric Scintillation during a Period of Saharan Dust (Calima) at Observatorio del Teide, Iz̃ana, Tenerife, and the Impact on Photometric Exposure Times

“…This is particularly relevant to Izaña, where placing results on scintillation in context requires an understanding of the impact of the Calima. The atmospheric extinction coefficient was determined each day using the technique described by Hale et al (2017). In brief, this involved logging the changing solar intensity measured throughout the day by our BiSON instrument, and fitting this for both morning and afternoon periods against the airmass calculated from the known solar zenith angle,…”

“…Figure1. Extinction coefficients and statistical distribution from Izaña, Tenerife, estimated with the Mark-I BiSON instrument using the technique described byHale et al [2017]. Morning and afternoon extinction values are estimated separately, shown in the top and middle panel.…”

Generalised Trends In Atmospheric Attenuation And The Importance of Accurate Extinction Calculation

“…The coefficient of extinction reached 0.138 magnitudes in summer and decreased to 0.102 magnitudes for light wavelength 510nm in winter at the Oukaimeden site in Morocco . Hale et. al (2017) analyzed data of over 30 years for 6 international observatories.…”