Night-Sky Friendly Lights aren't just about protecting views of stars. They're better for worker safety and cost efficiency, too.
Worker Safety: When working in a dangerous environment at night, it is natural to assume that more light is always better. However, over-lighting can decrease visibility and create dangerous situations. Lights aimed at a high angle can cause glare, forcing worker's eyes to adapt to bright conditions, thus losing their ability to see well in shadows. Glare can also prevent workers from seeing objects behind the light source. Eliminating glare results in improved visiblity and worker safety.
Aiming lights down, shielding them, using less intense lights, and avoiding harsh blue-white lights can eliminate glare.
Cost Savings: A light fixture that allows light into the sky is simply wasting energy and money. Aiming lights down reclaims that energy and directs it to where it can be useful. Using shielded lights and aiming them down, and using less intense (lower wattage) lights, can result in significant cost savings. By mounting lights high and aiming them low, fewer poles and fixtures are necessary to illuminate the area, resulting in further savings. Implementing these changes from the start typically costs nothing over traditional methods.
McDonald Observatory thanks the Apache Corporation for their support of our Dark Skies Initiative.