ATRONOMY – TELECOPE & OPTIC (46) CALCULATOR
Sky Glow Sqm
A precise tool.
What is the Sky Glow Sqm & How does it work?
Sky glow is the diffuse illumination of the night sky caused primarily by artificial light scattering in the atmosphere. It reduces the contrast of celestial objects and is a key indicator of light pollution. Astronomers quantify sky brightness using the Sky Quality Meter (SQM), which reports values in magnitudes per square arcsecond (mag/arcsec²). A higher SQM number denotes a darker sky. To relate SQM readings to physical luminance, the following conversion is used, allowing comparison with photometric units such as candela per square meter.
L = 10^{-0.4,(SQM – 14.2)}
L = sky luminance (cd/m²)
Parameters
Result
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Frequently Asked Questions
What is Sky Glow Sqm?
Sky Glow Sqm is a measure of artificial light scattering in the atmosphere, quantified by the Sky Quality Meter (SQM) in magnitudes per square arcsecond.
How does SQM relate to sky brightness?
A higher SQM number indicates a darker sky with less light pollution, while a lower number means more artificial light is present in the atmosphere.
Can I use this calculator for any location?
Yes, you can use this calculator to assess sky glow for any location by inputting local SQM readings.
What does a typical SQM value look like in a rural area?
Typical SQM values in rural areas range from 20.0 to 21.5 mag/arcsec², indicating minimal light pollution.
How can I reduce sky glow in my area?
To reduce sky glow, use shielded outdoor lighting, limit bright indoor lights visible from outside, and advocate for local dark sky initiatives.
Results are for informational purposes only and do not constitute professional advice.