The multi-spectral measurements are made using an array of 15° FOV Skye 4-channel sensors, each with 0-5 V signal output. When installed, these sensors are configured in a similar way to the Everest thermal infrared radiometers (bottom row in first picture), such that the six downward-looking sensors have the same incidence angle and footprints as the six PLMR beams. However, to correct for incident radiation, an upward-looking sensor with cosine diffuser is also installed. Each sensor weighs approximately 400g and has a size of 8.2cm × 4.4cm without the cosine diffuser or field of view collar attached). Two arrays of 4 channel sensors are installed, with the following (matched) spectral bands: