Sky Quality Meter measurements in a colour changing world
arXiv:1701.05019 · doi:10.1093/mnras/stx145
Abstract
The Sky Quality Meter (SQM) has become the most common device to track the evolution of the brightness of the sky from polluted regions to first class astronomical observatories. A vast database of SQM measurements already exists for many places in the world. Unfortunately, the SQM operates over a wide spectral band and its spectral response interacts with the sky's spectrum in a complex manner. This is why the optical signals are difficult to interpret when the data are recorded in regions with different sources of artificial light. The brightness of the night sky is linked in a complex way to ground-based light emissions while taking into account atmospheric-induced optical distortion as well as spectral transformation from the underlying ground surfaces. While the spectral modulation of the sky's radiance has been recognized, it still remains poorly characterized and quantified. The impact of the SQM's spectral characteristics on the sky brightness measurements is here analysed for different light sources, including low and high pressure sodium lamps, PC-amber and white LEDs, metal halide, and mercury lamps. We show that a routine conversion of radiance to magnitude is difficult or rather impossible because the average wavelength depends on actual atmospheric and environment conditions, the spectrum of the source, and device specific properties. We correlate SQM readings with both the Johnson astronomical photometry bands and the human system of visual perception, assuming different lighting technologies. These findings have direct implications for the processing of SQM data and for its improvement and/or remediation.
arXiv commentAccepted on MNRAS: ref. MN-16-1235-MJ.R2 Accepted 2017 January 17. Received 2017 January 12; in original form 2016 April 15
References in corpus (5)
- The new world atlas of artificial night sky brightness
- Contributions of artificial lighting sources on light pollution in Hong Kong measured through a night sky brightness monitoring network
- Night-sky brightness monitoring in Hong Kong - a city-wide light pollution assessment
- Night sky photometry and spectroscopy performed at the Vienna University Observatory
- Testing sky brightness models against radial dependency: a dense two dimensional survey around the city of Madrid, Spain
Cited by in corpus (31)
- Measuring night sky brightness: methods and challenges
- The nature of the diffuse light near cities detected in nighttime satellite imagery
- Systematic measurements of the night sky brightness at 26 locations in Eastern Austria
- Estimating the relative contribution of streetlights, vehicles and residential lighting to the urban night sky brightness
- Using all-sky differential photometry to investigate how nocturnal clouds darken the night sky in rural areas
- Colour remote sensing of the impact of artificial light at night (II): Calibration of DSLR-based images from the International Space Station
- Artificial light at night: a global disruptor of the night-time environment
- Effects of the COVID-19 lockdown on urban light emissions: ground and satellite comparison
- Night Sky Brightness Measurement, Quality Assessment and Monitoring
- Changes in night sky brightness after a countywide LED retrofit
- Magnitude to luminance conversions and visual brightness of the night sky
- Light pollution offshore: zenithal sky glow measurements in the Mediterranean coastal waters
- The throughput calibration of the VERITAS telescopes
- Monitoring transition: expected night sky brightness trends in different photometric bands
- Restoring the night sky darkness at Observatorio del Teide: First application of the model Illumina version 2
- Natural Night Sky Brightness during Solar Minimum
- Beyond CCT: The spectral index system as a tool for the objective, quantitative characterization of lamps
- Characterizing the zenithal night sky brightness in large territories: How many samples per square kilometer are needed?
- An enhanced version of the Gaia map of the brightness of the natural sky
- Variations on a classical theme: On the formal relationship between magnitudes per square arcsecond and luminance
- Quantitative evaluation of outdoor artificial light emissions using low Earth orbit radiometers
- Characterisation of Timau National Observatory using limited in-situ measurements
- Natural experiments from Earth Hour reveal urban night sky being drastically lit up by few decorative buildings
- Diverging evolution of light pollution indicators: can the Globe at Night and VIIRS-DNB measurements be reconciled?
- Photometric Catalogue for Space and Ground Night-Time Remote-Sensing Calibration: RGB Synthetic Photometry from Gaia DR3 Spectrophotometry
- Detecting changes in anthropogenic light emissions: limits due to atmospheric variability
- The Astronomical Hub: A Unified Ecosystem for Modern Astronomical Research
- Characterisation of night-time outdoor lighting in urban centres using cluster analysis of remotely sensed light emissions
- Beyond the Clouds: Advanced Data Analysis of a Dutch Sky Quality Meter Network
- Robotic observation pipeline for small bodies in the solar system based on open-source software and commercially available telescope hardware
- A photometric mapping of the night sky brightness of the Maltese islands