Infrastructure or equipment
ASTRON operates the LOFAR radio telescope, designed primarily as a scientific instrument for radio astronomy, with a dense core of receiving stations in the north-east of the Netherlands and fourteen stations internationally (six in Germany, three in Poland, and one in each of France, Ireland, Latvia, Sweden, and the UK). Radio astronomy observations are strongly affected by the ionosphere, leading to studies where bi-products from these can be used to obtain information on ionospheric structure, including dTEC measurements. LOFAR is also capable of dedicated observations designed to investigate the ionosphere, such as studies of ionospheric scintillation, and has been running such observations ad-hoc for several years.