What Can Be Done?
What Can Be Done?
Friends of Goldendale Observatory advocates improving, applying, and enforcing the City and County Lighting Ordinances. This includes using dark-sky friendly light fixtures, putting light where it is needed, during the time period it will be used, and at the levels that enhance visibility. While there are recommended levels of lighting for the purposes of safety, excessive and un-shielded lighting can diminish security and may even attract criminals, giving them places to hide in the deep shadows created by bright, glaring light:
To prevent sky glow, light trespass, and glare, use only "full-cutoff" - "fully shielded" light fixtures – those that put light only where it is wanted and needed, not wastefully into the sky or annoyingly onto neighboring properties:
Dark-sky friendly lighting takes into consideration a few basic design principles:
- Use “full cutoff” -- otherwise know as fully shielded -- light fixtures where no part of the light source or its reflective and refractive elements is visible above the horizontal.
- Use fixtures where light is aimed only downward where it is needed, not outward and upward where it is wasted.
- Putting a light higher up makes it easier to aim down for better ground coverage.
- Do not over-light an area. Reflected light can also contribute to light pollution, so it is important to use only enough light to do the job, and keep lighting levels to only what is actually needed.
- Use lighting which is "warm" -- amber light is not as harsh and is scattered less than “cool” blue-white light -- and protects the night sky much better.
- Turn off lights when not in use, or incorporate timers and sensors to shut off lights when not needed.
Is lighting needed all night? Landscape and facade lighting can easily be turned off after 10 pm or earlier. Many parking lot lights can also be turned off after hours. Most all lights can be controlled with timers or motion sensors, and this can save considerably on electricity costs. Outdoor lighting is often installed for “security” reasons - but if no one is watching is there really security? If a motion detector is used to control lighting and the light turns on, it is more likely to be noticed - and discourage intruders - than if the light is on continuously. Motion detectors can usually be an easy add-on for existing light fixtures and will quickly pay for themselves in reduced electricity costs.
There are many light fixtures that can replace poor outdoor lighting with excellent dark-sky friendly lighting - see here . Many of these fixtures have been reviewed to ensure that they minimize light pollution, and are actually better for lighting purposes:
For example, the typical un-shielded dusk-to-dawn outdoor "Yard Blaster" light fixture - shown at the top of this illustration - wastes over 45% of its light - and its electric bill - which is sent uselessly out sideways and up into the sky. On the other hand, the fully-shielded bottom fixture has no part of the bulb visible from the horizontal or above, and sends almost all of its light to the ground and is therefore nearly twice as efficient - see graph below. And if you replace the Mercury vapor lamp with a Sodium vapor lamp, you can cut the wattage in half and save almost 50% in energy costs with no loss of illumination.
Note the circular area of effective illumination in the included photograph. The fully shielded light fixture supplies 47% more illumination due to the redirection of light downward, verses the unshielded fixture, which is significantly less effective, but does a "better" job at completely ineffective and wasteful illumination - the result is glare, light trespass, and sky glow.
Source: City of Tumwater, WA. Staff report on outdoor lighting, Ordinance O2009-001.
When buying new or replacing old outdoor light fixtures, look to see if it carries the IDA certified label. Check with your local home improvement or hardware store - if they don't carry them, ask that they do!
Dark-Sky friendly lighting is available from Lowes and The Home Depot
Dark-sky friendly lighting does not require you to live in darkness or turn off all the lights at night – only the unnecessary ones. Light pollution is that rare issue that costs less to solve than to let it continue. Design and use outdoor light wisely and with common sense, save energy and money, and keep and protect our dark-sky for current and future generations.