McDonald Observatory Dark Skies

To protect the McDonald Observatory’s sensitive research from encroaching light pollution, Texas has built a robust legal framework to protect the area’s dark skies. In 1975, the Texas Legislature passed HB 57, enabling counties within 75 miles of the Observatory to regulate outdoor lighting. Under this authority, Jeff Davis County enacted one of the nation’s first dark-sky ordinances in 1976 to shield telescopes from artificial “sky glow.” As regional growth accelerated, SB 1481 (2001) made these protections mandatory for the seven counties surrounding the facility, and HB 2857 (2011) expanded standards to mitigate light from industrial and oil/gas operations. In 2022, these efforts scaled up to the international level with the designation of the Greater Big Bend International Dark Sky Reserve, covering over 15,000 square miles and extending into northern Mexico.