RT Journal Article T1 Absolute radiometric calibration of TESS-W and SQM night sky brightness sensors A1 Bará, Salvador A1 Tapia Ayuga, Carlos A1 Zamorano Calvo, Jaime AB We develop a general optical model and describe the absolute radiometric calibration of the readings provided by two widely-used night sky brightness sensors based on irradiance-to-frequency conversion. The calibration involves the precise determination of the overall spectral sensitivity of the devices and also the constant G relating the output frequency of the light-to-frequency converter chip to the actual band-weighted and field-of-view averaged spectral radiance incident on the detector (brightness). From these parameters, we show how to define a rigorous astronomical absolute photometric system in which the sensor measurements can be reported in units of magnitudes per square arcsecond with precise physical meaning. PB MDPI AG SN 1424-8220 YR 2019 FD 2019-03-17 LK https://hdl.handle.net/20.500.14352/13359 UL https://hdl.handle.net/20.500.14352/13359 LA eng NO © 2019 by the authors. This work was partially supported by Xunta de Galicia/FEDER, grant ED431B 2017/64 (SB), and partly developed within the framework of the Spanish Network for Light Pollution Studies, REECL (AYA2015-71542-REDT). CET and JZ acknowledge funding by the Spanish MICINN AYA2016-75808-R, by the Madrid Regional Government through the TEC2SPACE-CM Project (P2018/NMT-4291), and by STARS4ALL, a project funded by the European Union H2020-ICT-2015-688135. NO Unión Europea. H2020 NO Ministerio de Ciencia e Innovación (MICINN) NO Comunidad de Madrid NO Xunta de Galicia/FEDER NO Spanish Network for Light Pollution Studies, REECL DS Docta Complutense RD 9 abr 2025