Dark Sky Friendly Lighting Systems
A grave concern of many folks living in central Texas – particularly the more rural areas of the hill country – is our dark sky and light pollution. It’s a hot topic all over the country and one for which I try to stay informed. I’ve talked about this a few times on this blog (check here and here), but it’s always good to revisit such an important question for our environment.
In the photo here, the brightest light used is the equivalent of a 35 watt halogen light bulb and is an LED light source using only 6.5 watts of energy. Notice all of the down lighting to illuminate the walkways. This is a good example of dark sky friendly lighting.
Last week I attended a talk given by Mr. Bill Wren from the McDonald Observatory in the Davis Mountains of Texas. As you can guess, the topic was light pollution and how it can be reduced. Naturally he talked about the bad boys of outdoor lighting: sign lighting, street lighting, parking lots, sports complexes and oil/gas fields, to name just a few. These areas use HID (high intensity discharge) lighting like mercury vapor (which is no longer allowed to be installed), metal halide or high pressure sodium lighting. These light sources put out huge amounts of light, and when they are used in a fixture allowing the light to shine upward, they can really fill the sky with light. These fixtures, and how they are aimed, are the most offensive culprits of sky glow and light pollution.
I made a point of asking Mr. Wren about his thoughts on low voltage LED landscape lighting, as well. I was very happy to hear that he and I agree that a well-designed and properly installed landscape lighting system is a non-issue for light pollution. As a member of the International Dark Sky Association, NightScenes works hard to be respectful of their principles in all our designs; particularly in those neighborhoods with specific outdoor lighting restrictions, where we have a great deal of experience. While a billboard with eight lights may shine thousands of lumens into the sky with nothing to block any of the rays, the brightest light I usually specify for use on a project emits only about 300 lumens – and almost all of this light will be blocked by the item being accented. An important note to remember here is that good residential lighting design is not too bright, and fixtures should be aimed so they don’t shine straight into space.
Another concern for consumers is light trespass. This can be a huge problem. No one wants a light shining into their bedroom, or any other room for that matter; and poorly planned and directed lighting can make for some pretty upset neighbors. There should never be a reason for lights to shine onto someone else’s property. Properly installed outdoor lighting fixtures are aimed so the appropriate shield prevents glare, and the light does not shine into streets or an adjacent yard at all. If a lighting system is designed and installed correctly, the neighbors will actually like it – especially when they understand that these low light levels and the proper fixture aiming is not contributing to light pollution.
I was reassured by Mr. Wren’s presentation, hosted by the Hill Country Alliance, that the lower light output and proper aiming of low voltage LED landscape lighting is not a contributor to light pollution. The serious offenders that we all have a responsibility to monitor are the commercial light fixtures allowing large amounts of light to disrupt our view of the mesmerizingly beautiful starry night sky.
If your neighbors are not happy about your lighting shining into their windows or onto their property, please contact us here and maybe we can help.
