TENUM is a French company that has designed and manufactured a small educational sun-photometer named Calitoo. This instrument has been developed under the scientific and technical supervision of Dr. Phillipe Goloub and Eng. Luc Blarel from LOA (CNRS-University of Lille). Calitoo sun-photometers are used in the Global Learning and Observations to Benefit the Environment (GLOBE) program, which is a worldwide hands-on, primary and secondary school-based science and education program.

After manufacturing, the sun-photometers must be periodically calibrated to provide AOD measurements. In the periods 26 June – 3 July 2017 and 18-27 June 2018, a total of 200 Calitoo sun-photometers were calibrated using the Langley method at IZO. Furthermore, the new developments performed in the Calitoo were also tested at Izaña: new software capabilities, a real-time Angstrom Exponent computation and analysis, as well as the Calibot (CALItoo – roBOT) system for automatic sun tracking (still in testing phase).

Figure 1.- Top left and right, Calitoo sun photometer calibration campaigns in 2017 and 2018 at Izaña Atmospheric Observatory. TENUM Calitoo activities at IARC: preparations and measurements for Langley calibration performed by Frederic Bouchar and Stéphane Villeneuve (bottom left) and Calibot tests (bottom right) (images courtesy of TENUM).