In November 2021, Pr. Martin Aubé from the University of Sherbrooke (Canadá) installed the new version of the multispectral Color Sky Quality Meter (CoSQM version 2) in Izaña Observatory. The CoSQM is a portable device which samples the multispectral properties of artificial light scattered by the atmosphere. It is a convenient tool to estimate light pollution and its impact on the environment. CoSQM is an instrument composed of a filter wheel with four different spectral transmittance in the visible range (clear, red, blue, green), placed on a step motor in front of a Sky Quality Meter.

The device comprises a Raspberry pi open source linux computer so that it can be reproduced by anyone. CoSQM also comprises a camera module. The instrument can be operated remotely via the SSH protocol and the data may be accessed via an integrated web server. This device provides data to demonstrate how humankind can affect their own nocturnal environments. Colour detection capability is an important improvement over existing non-imaging detectors in the context of the drastic change in the colour of light pollution provided by the transition to LED technology.

Figure 1.- Dr Martin Aubé at Izaña during the installation of the new COSQM version 2 instrument in November 2021.

This new and improved version of the COSQM adds improvements on the camera, enclosure, motor, WIFI and filter wheel. It also includes a high quality raspberry pi. In particular, this new system reacts better to high temperature conditions.