SG-WAS: a new Wireless Autonomous Night Sky Brightness Sensor

TL;DR

SG-WAS is a low-cost, autonomous wireless sensor for measuring night sky brightness, capable of long-term operation and precise calibration, suitable for remote deployment without infrastructure.

Contribution

This paper introduces SG-WAS, the first fully autonomous wireless NSB sensor that combines low cost, long autonomy, and precise calibration for remote sky brightness monitoring.

Findings

Operates up to 20 days without solar irradiance

Can remain hibernating for at least 4 months

Calibration uncertainties below 0.02 mag/arcsec$^2$

Abstract

The main features of SG-WAS (SkyGlow Wireless Autonomous Sensor), a low-cost device for measuring Night Sky Brightness (NSB), are presented. SG-WAS is based on the TSL237 sensor --like the Unihedron Sky Quality Meter (SQM) or the STARS4ALL Telescope Encoder and Sky Sensor (TESS)--, with wireless communication (LoRa, WiFi, or LTE-M) and solar-powered rechargeable batteries. Field tests have been performed on its autonomy, proving that it can go up to 20 days without direct solar irradiance and remain hibernating after that for at least \mbox{4 months}, returning to operation once re-illuminated. A new approach to the acquisition of average NSB measurements and their instrumental uncertainty (of the order of thousandths of a magnitude) is presented. In addition, the results of a new Sky Integrating Sphere (SIS) method have shown the possibility of performing mass device calibration with uncertainties below 0.02 mag/arcsec$^2$. SG-WAS is the first fully autonomous and wireless low-cost NSB sensor to be used as an independent or networked device in remote locations without any additional infrastructure.