Abstract
Several networks of Sky Quality Meters show long-term trends in measuring the night sky brightness. Causes of this variation could be ageing of the instruments and variations of the sky emission. The data from Ekar Observatory (Italy) are here considered.No significant ageing effect was detected on 9-year-old housing windows. A 9-year-old IR blocking filter shows a variation of its spectral transmittance up to 80%.No trend on the SQM output was found due to only the variation of the spectral distribution of the night sky emission. Together with ageing of the IR blocking filter, it causes a reduction of the SQM output of about 0.01magSQMarcsec-2 per year.Slow trend of the aerosol optical depth suggests the air near the considered site is changing towards less polluted conditions. It reduces scattering of the artificial light and consequently sky glow in the light polluted considered site.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
