Why is it important to have dark skies? It’s not just so people can see the stars, although that is a very good reason in and of itself. Night skies are connected to the natural world. Protecting the night sky from light pollution is critical to the environment, wildlife and our quality of life. Less than 100 years ago, everyone could look up and see a spectacular starry night sky.  Now, for most people, this is not possible. The increased and widespread use of artificial light at night is not only impairing our view of the universe, but it is also adversely affecting our environment, our health and our energy consumption. There are several videos on YouTube that give a very succinct explanation of the problem, such as “Why the Stars are Disappearing” and “Light Pollution 101” by National Geographic.

Here are some impacts of light pollution:

Light pollution has a major effect on mammals, birds, reptiles and insects. Circadian rhythm (the day and night cycle) plays an essential role in controlling the characteristic behaviors and physiology of all animals. Significant events of animal life such as growth, locomotion, development and reproduction are highly dependent on the proper balance between day and night. When unwanted artificial light enters their surroundings, it causes severe alterations in the natural cycles of animals’ activities. Light pollution may also affect the reproductive system of these insects and animals and it is also responsible for changes in the migration pattern of birds. Did you know that excessive light decreases the ability of zooplankton to consume algae from the water surface? This leads to algae blooms that may reduce water quality and also disturb the flora of aquatic ecosystems. In simple terms, light pollution interferes with the natural cycles and rhythms of daily life in the environment.

Excessive light can affect humans in a variety of ways. It can cause eye irritation and redness, headaches, fatigue, stress and anxiety in people who are quite often exposed to over-illumination. Long-term exposure to light pollution at night may affect the production of melatonin which is an essential component for a strong immune system.  

Light pollution is not only showing negative implications on humans, animals, plants and the environment, but it is also adversely affecting astronomy. When light scatters in the sky, it minimizes contrast in the atmosphere and astronomers find it quite challenging to view and observe the night sky. When excessive light enters a telescope, it makes observation very difficult due to extreme glare. This is why McDonald Observatory worked with the local community to create a very successful dark skies environment.

Wasting energy is one of the major impacts of light pollution. It requires a lot of money and energy to light up public places and communities. The general mindset is that people are only paying for the amount of light they are using, but no one considers how much energy they are wasting. In short, over-illumination is just wastage of electricity, money and natural resources along with incrementally polluting our environment.

The unfortunate fact related to light pollution is that it is created only by human-made causes. Hence, it is we who can make the necessary changes:

• Ask yourself – do you need to keep your landscaping lights on all night? Cordillera Ranch basically shuts down after sun  set. Why not turn off all your outdoor lights within an hour after sunset. It will save energy and promote a dark sky.

• If you want to keep some external lights on, change out the bulbs to the lowest wattage and warmest color temperature    LED you can find.  

• The Cordillera Ranch Design Guidelines have several other restrictions for lighting that, if followed, will help minimize    light pollution, including:

o Fluorescent, metal halide, low-pressure sodium lamps, exposed bulbs and wrap-around lenses   are prohibited;

o Down lighting is encouraged;

o Exterior flood light lamps must have housing at least 8 inches long and the housing must extend at least 3 inches beyond the bulb, and the maximum angle from the wall shall not exceed 30 degrees;

o Traditional low-voltage exterior lighting should be limited to no more than 45 watts on address markers and entry gates and no more than 75 watts for exterior-mounted flood lamps. For LED lighting, it is important to minimize the amount of blue light emitted (that color spectrum brightens the night sky more than any), so the color temperature of LED lights should not exceed 3000 Kelvins (and again should be pointed downward and shielded).

o Exterior and landscaping lighting shall be installed to minimize the visibility of the light source and to minimize the pollution of the night sky.

“The clear night sky is a major attraction for people moving to the Texas Hill Country,” noted Cordillera Ranch Development President, Charlie Hill. “Since Cordillera Ranch began back in 1997, limiting light pollution to preserve this beautiful and unique natural resource has been an important priority for us, and we’re currently working to update the existing lighting restrictions in the Cordillera Ranch CCR’s and Design Guidelines to enhance the existing stringent guidelines aimed at protecting the sky for years to come,” Hill continued.

Just doing these small steps can help Cordillera Ranch be a true dark sky community. For more information and guidance on outdoor lighting that will help preserve our light school, check out this great resource from the International Dark Sky Association: www.darksky.org/our-work/lighting-for-citizens/lighting-basics.

Sources:

www.texas.darksky.ngo
www.earthreminder.com/harmful-impacts-of-light-pollution
www.darksky.org

“Deep in the Heart of Texas,” 
Composer: Don Swander, Lyricist: June Hershey