BRITISH CROWN COPYRIGHT, THE MET OFFICE / SCIENCE PHOTO LIBRARY BRITISH CROWN COPYRIGHT, THE MET OFFICE / SCIENCE PHOTO LIBRARY
Point visibility meter (PVM). This is the sensing part of this instrument, which is a type of visibility recorder. Also called a nephelometer, this device typically uses a beam of light and a light detector to measure the amount of fog, pollution, or smog present. More advanced models (as here) use laser beams or radar. This model is from Plessey Radar, and was developed in the 1970s. Equipment like this is used to gather data for the Met Office, the UK's national weather monitoring and forecasting service.
Model release not required. Property release not required.