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Volume 1, Issue 1
Understanding How Light
Fixtures Affect Sky Glow –
And Why It Matters
Skyglow, also known as light pollution, is the brightening of the night sky as the result of excessive and inappropriate artificial lighting.
Outdoor lighting at night
Photo: Light pollution is an increasing problem threatening astronomical facilities, ecologically sensitive habitats, wildlife, and energy use.
The Department of Energy’s Pacific Northwest National Laboratory (PNNL) wanted lighting engineers, designers, and urban planners to have more information from which to make informed lighting decisions about the factors leading to sky glow.
Warm-white LEDs mimic the moon
Photo: The Bortle Scale is a nine-level numeric measure of the night sky’s brightness in a particular location. It quantifies the astronomical visibility of celestial objects and the interference caused by light pollution (photo credit to Skyglow Project).
The 2017 joint study on sky glow uncovered factors beyond color temperature that contribute to sky glow, including atmospheric conditions and spectral power distribution (SPD). An outcome of the study was the development of the Sky Glow Comparison Tool.
This new way of looking at factors influencing sky glow and a tool that helps measure and compare lighting fixtures is important. Protecting dark skies and decreasing light pollution will have positive effects on the environment and the wellbeing and health of all living things, from plants and animals to humans.
As a holistic physician, Dr. Sara Warber, Professor Emerita, Department of Family Medicine, at University of Michigan, has a strong interest in human wellbeing. Dr. Warber's understanding of the connection between nature and physical and emotional wellbeing comes from her experience growing up. "I was happiest when I was outside," she explains. "And that is still true. Humans are rejuvenated by being outside."
Dr. Warber is interested in the full range of outdoor experiences, nighttime included. "Viewing the night sky is awe-inspiring and humbling. I am a little speck in this huge unfolding place. Being humbled, in this sense, feels good and increases my wellbeing. I feel connected to this huge place but also small. I can let go of my small preoccupations in the midst of this immense world.
Light pollution
Photo: Light pollution is an increasing problem threatening astronomical facilities, ecologically sensitive habitats, wildfire, and energy use.
"One of the problems with overly lit nights is that they block humans from the broader experience of the darkened environment," Dr. Warber continues. "But people need to feel safe in order to have an increased sense of wellbeing. LED technology is an incredible boon to people and our need for light. LED light can be environmentally manipulated. We can be more selective about the brightness, color, and purpose of that light-and expose people to nature 24 hours a day."