Stargazing in San Antonio? Dim the Light Pollution

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A view of downtown at night from the Pearl brewhouse’s copula. Photo by Scott Martin.

A view of downtown at night from the Pearl brewhouse’s copula. Photo by Scott Martin.

Do you get enough sun? If you live in Texas, you probably do just fine – maybe even too much sun. But do you get enough starlight? Do you get enough darkness?

“Texas has taken the lead on lighting control,” said Bill Wren of the McDonald Observatory. Light pollution – which occurs when light is unnecessarily directed up or out, rather than down where it’s needed – is a growing problem across the globe. Studies estimate that it is impossible to see that Milky Way from more than two-thirds of the planet. Approximately 99% of the population in the United States lives in light-polluted areas. It’s an economic burden, too, as tens of billions of dollars are wasted every year by sending light upward, as documented in dramatic aerial light pollution images.

Light pollution's past and future in the U.S. Image courtesy of McDonald Observatory.

Light pollution’s past and future in the U.S. Image courtesy of McDonald Observatory.

But this is changing, and Texas is at the forefront of enacting solutions to light pollution. Excess lighting is not only ineffective and inefficient, but it also has an unquantifiable effect on our health and culture.

Increasing studies have linked an absence of darkness with lower melatonin levels, which in turn are linked with breast and prostate cancer. Further, light pollution has disrupted everything from the migration of certain bird species to the photosynthetic cycles of deciduous trees. The effect on culture, and the inspiration a clear night sky has provided for literature, mythology, art and science, is less tangible, but no less significant.

As light pollution maps demonstrate, there are parts of San Antonio where the stars are almost completely obscured and the night sky is significantly discolored. The city casts a bright glow on the horizon as far away as the Bandera area of the Hill Country.

Light pollution map of San Antonio and surrounding areas. Image courtesy of Google Earth and David Lorens (University of Wisconsin-Madison). Click here for map key.

Light pollution map of San Antonio and surrounding areas. Image courtesy of Google Earth and David Lorens (University of Wisconsin-Madison). Click here for map key.

“The pervasive standard for a long time has been ‘the more light the better.’” Wren said. We are afraid of the dark.

In fact, light pollution is one of the simplest environmental problems to solve. The answer is as easy as replacing compact fluorescent and incandescent bulbs with longer-lasting, energy efficient LED (Light-Emitting Diodes) bulbs and shaded fixtures, which direct light where it’s needed. Easier still: just turn off unnecessary lights.

Homeowners and businesses, however, are still concerned with the upfront cost of lighting and fixtures, particularly where retrofitting is required, as this week’s New Braunfels’ City Council meeting on a proposal to increase outdoor lighting regulation proves. Boerne already has an ordinance in place requiring that an Illumination Plan be submitted for new building and development, and regulates outdoor lighting, including requisite shields, color control, cut-off capability and timing of exterior lights.

Hill Country towns are particularly interested in preserving the true Texas Hill Country experience, of which those “stars at night…big and bright” are an essential part.

In 2012, Austin set aside $15 million to replace the bulbs and fixtures on approximately 70,000 streetlights with LED bulbs and flat-glass lenses that focus the light downwards. Laura Eakins at the University of Texas Department of Astronomy estimates that the change has stabilized, if not decreased, light pollution in the city, even as it expands.

San Antonio is well on its way to matching that. In 2012 the San Antonio City Council approved a plan to upgrade the city’s streetlights from high-pressure sodium bulbs to light emitting diodes (LEDs). CPS Energy, in association with the city of San Antonio, has already replaced 25,000 out of approximately 70,000 street lamp bulbs. This represents lighting on all major thoroughfares.

CPS Energy estimates that this will save the city more than $1 million per annum, with significant further savings anticipated in reduced energy and upkeep costs. San Antonio will soon be implementing pilot programs to replace neighborhood streetlights, which comprise the majority of the remaining fixtures (highway streetlights are regulated by the Texas Department of Transportation).

The technical difference is traditional bulbs work by heating a piece of metal so hot that it emits light, while LEDs excite electrons, which then emit light.

Tracy Hamilton of CPS Energy explained that LED bulbs installed in San Antonio use approximately 80 watts, versus a High Pressure Sodium bulb’s 250 watts. Sodium bulbs last approximately five years, while LEDs last up to 15. LEDs can be made to focus light.

In November 2014 CPS Energy partnered with H-E-B for a limited-time sale of LED bulbs for 97 cents (usually priced at $7), which was a resounding success. One we can only hope they’re inclined to repeat in the future.

But, Hamilton said, the benefits for San Antonio extend beyond reduced light pollution: all LEDs purchased by CPS were made here in San Antonio by GreenStar, a company founded by Paul Duran in Boerne in 2009. The company employs over 40 people and sources local parts and materials whenever possible.

This street switched to LED streetlights (bottom) from high-pressure sodium bulbs (top). Photo courtesy of McDonald Observatory.

This street switched to LED streetlights (bottom) from high-pressure sodium bulbs (top). Photo courtesy of McDonald Observatory.

When Duran founded the company, he noticed that none of his engineers came from San Antonio. He pledged that for every LED bulb the city of San Antonio purchased from GreenStar (that’s 25,000 so far, and 70,000 anticipated), the company would put $10 towards the University of Texas San Antonio’s College of Engineering for the college’s first energy-related endowed professorship.

GreenStar now supplies LEDs internationally, and continues to grow.

As Wren points out, reducing light pollution isn’t just about changing fixtures: it’s about education and awareness. In San Antonio, he points to The Rim shopping center as an excellent example of effective lighting. The Rim falls under San Antonio’s lighting ordinance restricting lighting within five miles of a military base or training site (Camp Bullis, in this case), which require darkness for training purposes. Although the city has no other lighting ordinances in place yet, they are becoming increasingly common nationwide.

There also are three Texas State Codes regulating outdoor lighting, including in the vicinity of observatories (within 28,000 square miles in the case of the McDonald Observatory), as well as regulations regarding outdoor lighting in state-funded areas (for example, a state university parking lot).

“The places you can go to see a naturally dark sky are rapidly disappearing,” Wren says, but there is hope that we could see the stars at night above San Antonio again.

You can find more information at the Texas branch of the International Dark-Sky Association, a non-profit organization founded in 1988, fighting to “preserve the night.”

The light pollution from cities spills over into the Texas Hill Country. Photo courtesy of McDonald Observatory.

The light pollution from cities spills over into the Texas Hill Country. Photo courtesy of McDonald Observatory.

*Featured/top image:  A view of downtown at night from the Pearl brewhouse’s copula. Photo by Scott Martin.

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Seeing the Milky Way in San Antonio — The Easiest Environmental Problem to Fix

The Tiny House Movement: Living Large in Small Spaces

Conversation: The Case for Good Architecture in the Alamo City 

Low Impact Development: How San Antonio Can Profit From Sustainable Design

13 thoughts on “Stargazing in San Antonio? Dim the Light Pollution

  1. In the western states (WA, OR, CA, NV, CO, UT, and AZ), dark sky ordinances are used by cities run by the LDS (Mormon) Church.

    Are Austin and San Antonio run by the LDS Church?

    Cities without streetlights are not safe for cyclists and pedestrians at night. But in LDS cities, that works fine since they are not out as much as night compared to non-LDS run cities.

  2. I hope over-illumination awareness is evoked at the residential level as well. SA-folk seem to love their huge HomeDepot “security” lights — one beacon on each side of the house. Studies have shown such lights actually facilitate break-ins because the contrast between the illumuniated areas and the dark areas in the shadows offer burglars an obscured pathway to the home itself. And don’t get me started on my neighbors’ patio lights that shine directly on my windows and patio doors, illuminating 4 rooms in my house — even with curtains on the windows! And I wish I could sit on my patio without being blinded by lights from neighbor on left and neighbor behind me. Dimmit, dammit! Better yet, turn ’em off. My house is completely dark when I’m not home or sleeping and I’ve never had a break-in problem (even without three backyard bark-at-everything-and-anything dogs as my terrified neighbor has).

  3. Sigh. My husband is an astronomer and has a huge telescope that he has to drive out 3+ hours from SA to be able to see much. He studies the light pollution maps endlessly. We just returned form Ft. Davis, TX, where the street lights lighten the street more the enough, yet cause very little light pollution.

    Meanwhile, at home in Southtown, the church across the street has a floodlight on all night so we need blackout curtains in our bedroom to sleep during the night.

  4. we should…. Bill Wren is a huge advocate about this…. this can be a well noted idea for San Antonio… we arne’t that big… but we can big enough to make a difference and first for a “city” to be night sky friendly…. I started taking my son to Ft. Davis and Big Bend because I told him when I lived over seas we saw THE STARS…..then we moved back to the states and um…WHAT HAPPENED… but then again that was NY and then here…LOL…. but that would be FANTASTIC if San Antonio owned night sky friendly.. I mean we got an adorable planetarium….why not?

  5. Light pollution will always affect any city of density. It is a natural progression of a growing city with more people in it. If you want to see the night sky, travel out and I am sure you will fulfill your stargazing needs. A well lit city is a safer city.

    I am happy that CPS has installed LED based street lights for energy efficiency.

    • We shouldn’t have to “travel out” to see the wonders of the night sky. We should be able to go in our backyards and enjoy the night sky. It is not exactly ideal to travel for 20 miles or so every night to stargaze.

      A well-lit city is not necessarily a safer city. Poorly-shielded light fixtures can pose a bigger problem than no light due to glare. The idea that “more light is better” is false. More light will not prevent accidents or crime. More light will only give the illusion of safety. Responding to an incident by adding more light is the easiest way to do something without actually resolving the issue while looking like you are. The city of Chicago, IL is a perfect example of how adding more light does not make you any safer.

      You are correct, light pollution will always affect any city. However, you can always reduce your impact on the environment. The city of Flagstaff, AZ has done a lot to reduce their light pollution. They have replaced all of their city’s street lights with fully-shielded LPS fixtures. They have also set the maximum measurement for foot candles and lumens for businesses low enough to where they can provide enough light without causing a negative effect on the environment around them. For a city of its size and population, it only produces the amount of light pollution you would see from a small town. They have been recognized as the world’s first International Dark-Sky City. It has not only greatly helped astronomical research in the area but has also greatly increased the city’s eco-tourism.

      LED lights are the worst choice for outdoor lighting because their white light does not allow other light to pass through. They also have many negative effects on the environment due to how much they resemble moonlight and can confuse other creatures and living organisms. LPS lights are the best choice for outdoor lighting because they provide the widest gaps through which other light can pass. Their amber color is also environmentally friendly and will not disturb other creatures and living organisms. That is why observatories and many places for outdoor recreation such as regional and national parks choose LPS lighting.

  6. Reducing light pollution is a much bigger story than seeing stars. And, light pollution doesn’t have to affect an area just because of dense population. A well-lit city doesn’t have the pervasive glare and light trespass that San Antonio has. This story makes San Antonio and GreenStar look like they’re doing a great job with these LED lights. Take a walk along S. Main Avenue near the little park owned by the San Antonio Housing Authority. The new LED lights create so much glare that you can’t see the sidewalk more than a few feet in front of you much less into the park. That’s not safe. And, those new LEDs and other lights are creating excessive light trespass in many areas of San Antonio. Check out the 100 block of N. Josephine Tobin where residents note about the new LEDs: “We have been bullied out of our house where we have lived for over 50 years. We are paying property taxes on a home that is now uninhabitable at night. This city has stolen everyone’s property rights wherever these lights are installed. We can’t even sit on our front porches at night. If we do, we have to cover our eyes with our arms.” How nice that the City of San Antonio is saving money on energy costs except that by doing so they have introduced very blue-rich light into the environment which damages our health at night. I’m glad the article mentioned the fact that artificial lights suppress melatonin. I wish they had mentioned that these particular LEDs suppress your melatonin more that many other lights. A resident who lives by these new lights wrote this about the LEDs in San Antonio, “These LED lights sicken me. I look and feel horrible all the time. I had to get an apartment just to sleep.” It would be great to see a follow up article with an interview of Dr Russel Reiter, Professor at the UT Health Science Center in San Antonio and one of the top researchers in human melatonin.

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