Lyndon B. Johnson National Historical Park wanted everyone to see the Texas White House.
Seeing the Texas White House at night came at a cost.
Left image
With exterior lighting.
Credit: Robert C. Pettengill, Jr.
Right image
Without exterior lighting.
Credit: NPS Photo
Exterior lighting at the Texas White House has a huge impact. With the lights on, there is a dramatic lighting effect on the historic home, however, a blinding glare also prevents visitors from being able to view the night sky. Once the lights are turned off, the sky is easily visible. Slide the arrows back and forth across the photo to see the difference.
The Hill Country night skies are a critical natural and cultural resource at Lyndon B. Johnson National Historical Park. In order to best preserve this resource, staff and experts have worked to inventory park lighting and make modifications that reduce light pollution while maintaining the historic integrity. One recent project focused on the Texas White House—a valuable historical resource in the Hill Country. Aided by the International Dark Sky Association and other night sky experts, the park was able to develop and implement a plan to make this building “night sky friendly.” The park took simple steps, including installing timers and changing certain bulbs, in order to make a significant impact on local night skies.
Doing Our Part
The first step was determining what light fixtures currently existed on the LBJ Ranch. The park conducted a lighting inventory, noting the location and type of each fixture, and whether it was “night sky friendly.” To be night sky friendly, exterior lighting fixtures should project light downward, not at the horizon or into the sky, and should produce a warm, yellow light.
This is an aerial photo of the Texas White House and associated buildings. Each dot represents a light fixture.
Based on this inventory, the park modified the light fixtures by adding either timers or shields. All the bulbs that exceeded a color temperature of 2500 kelvin were replaced with warmer bulbs..
Doing Your Part
You can participate in night sky preservation in your local neighborhood or even right in your own home by taking an inventory of your lights and making the appropriate modifications.
Tips for a Complete Inventory
Look closely around structures and parking areas
Create a simple map of all exterior lighting fixtures
Ask yourself: “Can I see light from the bulb along the horizon?”
Retofitting Lights that are Not Night Friendly
Thankfully, lighting retrofitting can take many forms—many of which are simple to undertake. These can include light fixture modification (e.g., shielding, adding timer switches or motion sensors) or through replacing bulbs with lower temperature (i.e., “warmer”) bulbs.
Light should be directed downward, NOT upward or horizontally
Bulbs should emit a "warm" color, less than 2100 K (kelvin)
Timers and motion sensors are an easy way to keep lights, but make them more night sky friendly
Remove unecessary lights
The best light fixtures shield light bulbs and prevent light from escaping upwards into the night sky. The best bulbs are a warm, yellow color of 3000 K (kelvin) or less.
Park Historian/Resource Specialist Alex Shane spoke to members of the University of Texas Lifelong Learners program on October 7, 2020 about the park's efforts to earn a Dark Sky Park designation from the International Dark Sky Association. Although he focused on improvements the park is making to enhance night sky viewing, many of those same improvements can be done just as easily in each of our own backyards! With a little effort and cooperation among neighbors, we can all experience star-filled nights!
Do you miss seeing stars at night? Good news! Excess light shining up into the sky—light pollution—which is preventing amazing night sky views, is a curable condition! Join Wayne Gosnell as he speaks about the causes and solutions for light pollution. Mr Gosnell is a member of the International Dark Sky Association, the night sky team of the Texas Hill Country Alliance, and a member of the Blanco County Texas Friends of the Night Sky.
Take a walk with Alexander Shane, park historian, as he travels between the Sun and Neptune! That is, as he walks on a small-scale version of the the distance between the Sun and Neptune laid out on the LBJ Ranch.
