Intercomparisons of nine sky brightness detectors

• Published in: Sensors (Basel, Switzerland) Vol. 11; no. 10; pp. 9603 - 9612
• Main Authors: den Outer, Peter, Lolkema, Dorien, Haaima, Marty, van der Hoff, Rene, Spoelstra, Henk, Schmidt, Wim
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.10.2011; Molecular Diversity Preservation International (MDPI)
• Subjects: artificial lighting; Calibration; Darkness; Extraterrestrial Environment; Humans; intercalibration; intercomparison; Light; light pollution; Luminescent Measurements; Netherlands; night sky brightness; Optical Phenomena; Optics and Photonics - instrumentation; Optics and Photonics - methods; Sensors; Sky Quality Meter; Netherlands; Canada; light pollution; intercalibration; artificial lighting; night sky brightness; Sky Quality Meter; intercomparison
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s111009603

Nine Sky Quality Meters (SQMs) have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across The Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between ±14%. Individual night time sums range from -16% to +20%. Intercalibration reduces this to 0.5%, and -7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 ± 0.003 mcd/m(2) on 12 April, and the largest value was 5.94 ± 0.03 mcd/m(2) on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent.