The Cimel CE 318-2 is a portable automatic tracking sun photometer measuring sun and sky luminances in 8 filters over visible to near infrared wavelengths. The CE 318-2 is fitted with filters at 340 nm, 380 nm, 440 nm, 500 nm, 675 nm, 870 nm and 1020 nm for measuring atmospheric aerosol optical thickness, and a filter at 939 nm for measuring atmospheric water vapour.
The instrument automatically computes the position of the sun and tracks its movement. It can be programmed to collect data in manual or automated sequences of measurements, which include almucantar and principal plane scenarios.
Two movie sequences (*.mov) are available which to download below. They show the Cimel performing Almucantar and Principal Plane measurements.
The facility presently has its two Cimel sunphotometers sited at Chilbolton in Hampshire and in Edinburgh. We also support the CEH sunphotometer at Wytham Woods near Oxford. All three sunphotometers are part of the AERONET network, managed and run by NASA at the Goddard Spac Flight Center. All the active sunphotometers within the AERONET network are annually calibrated and inspected at GSFC providing excellent site to site inter-comparison of the measurement data.
The NERC FSF sunphotometer based at Edinburgh is also available for loan on campaigns where automatic tracking is essential and not covered by our hand held MicroTop sunphotometers. Apply for the Cimel sunphotometer through our standard loan application form.