How You Can Help Preserve the Night Sky

Minimizing Light Pollution is Simple

Follow these helpful tips:
  • Use outdoor lighting only when needed
  • Only light the area that needs light
  • Minimize blue light emissions
  • Utilize fully shielded light fixtures outdoors
  • Close blinds at night to keep indoor light inside
  • Look for the International Dark Sky Association (IDA) fixture seal of approval
  • Spread the word!

Against Blue Light

To protect yourself from blue light, use dim red lights. Red light compared to the other colors in the spectrum are the weakest, while blue is the strongest.

Use lighting with 3000 Kelvin color temperature or below. You can look at the light’s packaging for its color temperature. The light’s temperature is a measurement of lighting. Since blue light can simulate daylight and has the most strength, it easily brightens the night sky. The higher the color temperature the more blue it has. Therefore, use warmer lights (3000K or less) because they have the least effect on the night sky.

You can use blue blocking glasses when using electronic devices with screens. Apps such as F.lux, Lux, twilight, and night shift (iOS) filters out blue light from the screen come nighttime. This helps protect you from some sources of blue light.

IDA Seal of Approval

When buying new lights check if the packaging has the international dark sky fixture seal of approval. This ensures that the bulb is dark sky friendly.

Fully Shielded

Full cutoff or fully shielded light fixtures are ideal as they control the direction of the light. They aim at the ground and don’t let any light to go directly towards the sky preventing sky glow, light trespass,and glare. A fully shielded fixture indicates no light above a 90-degree angle.

Types of Lighting

LEDs are becoming more commonplace. And with metal halides they have many benefits that saves energy and light pollution. Unlike most lighting, they are able to be dimmed and turned off when need be or not in use. However, this type of lighting have large amounts of blue light. So make sure they are low temperature LEDs. The same goes for Low Pressure Sodium (LPS) and High Pressure Sodium (HPS) lighting.

Illustrations by Bob Crelin © 2005. Rendered for the town of Southampton, NY. Used with Permission.


New York City at night. Lights leaking into the sky.

Light-Pollution-Are-the-Stars-Out-Tonight-NYC-Untapped-Cities (2)

Energy Waste

Much of what contributes to light pollution is light being improperly used. The goal of lights is to illuminate the ground to provide visibility to the user. Most light fixtures shine on the ground, however they also aim at the sky. Lighting that allows light to spill into the sky promotes sky glow, decreasing our visibility of the stars, and disorients nocturnal animals.

Illuminating the sky negatively affects us, our wildlife, and our electricity bill. There is no need to light up the sky when the goal is to see the ground. Light going to the sky because of unshielded fixtures is wasteful, which in turn is a waste of energy. The International Dark Sky Association estimates that a third of all outdoor lighting in the U.S. is wasted because of unshielded lights. That’s energy that could have been used for something more productive. The wasted energy amounts to about $3.3 billion with the discharge of 21 tons of carbon dioxide each year!

Motion Sensor

Motion sensor lighting allows light when it is needed. Then turns off after a short time later when it’s not needed. Sensitivity should also be adjusted to prevent unnecessary lighting. And, dimmer switches are a plus as it controls brightness.

Rule of thumb:

Light where it’s needed, when it’s needed, and only as bright as needed.

By doing dark sky you can save money on your electricity bill and do good for the night sky, wildlife, and your health.

Information gathered from these resources:

International Dark Sky Association: Outdoor Lighting Basics and Get Involved