The Scope of Light Pollution

Night Skies Map Set

Night Skies Map Set5

Not only is light pollution an issue; it is an issue that is trending more serious with development.  The expansion in light-polluted areas shows that this is an issue which must be addressed.      

Field Data Light Pollution

Texas at Night credit NASA

One of the features of a formal certification as a Dark Sky Place is the need for an ongoing program measuring night sky brightness. 

One method of measurement is to use light meters.   A second method, used by the Globe At Night program, has people from all over the world measure by comparing the stars visible at their location to eight charts.  The number of visible stars corresponding to the chart determines the amount of light pollution in the sky.  

Lakeway Light Pollution Survey

Photo overlooking lakeway at night with many house lights on producing light pollution.

Some ZAPCO commissioners and city staff conducted a survey of Lakeway at night to evaluate our levels of light pollution.  We found that residential and commercial areas were generally compliant with Dark Sky principles, with only occasional issues with glare, light trespass, and excessive intensity.  

Certification as a Dark Sky Place

Dark Sky Billboard

There are pros and cons to seeking a formal designation as a Dark Sky place.   


  • Certification is a promotional tool that can help raise awareness of the issues of light pollution and dark skies.
  • The formal Dark Sky program provides a framework to guide advances in dealing with light pollution and dark skies. 
  • Numerous exceptions from the standards of the Model Lighting Ordinance have been granted to other cities which have formal certification, so it is not as complex as it initially appears.  


  • Formal certification is an involved process that takes three to five years to complete. 
  • Formal certification imposes obligations on the city and on residents, including ongoing monitoring of brightness, ongoing education programs, a strenuous light curfew, and a timeline for revoking grandfathered non-compliant lighting.  
  • Field measurement of light is complex and requires special training and tools.  
  • Since the light survey determined that Lakeway is generally compliant, addressing light pollution and dark skies issues should focus on new development rather than existing sites.

    Based on these pros and cons, the city has decided to implement Dark Sky principles without pursuing a formal certification as a Dark Sky place.  This approach maximizes the benefits of the program without imposing ongoing costs.