Preserving the Dark West Texas Night Sky at McDonald Observatory Mark T. Adams and William R. Wren University of Texas at Austin - McDonald Observatory HC 75, Box 1337-MCD Fort Davis, Texas U.S.A International Conference on Light Pollution March 2002 La Serena, Chile

Presentation Outline  McDonald Observatory overview  Lighting program goals  Lighting ordinance model  Public education  Conservation partnership  State of Texas support  Summary

McDonald Observatory Overview  Three missions  Education  Research  Public Outreach Five professional research instruments on Mount Locke and Mount Fowlkes Five professional research instruments on Mount Locke and Mount Fowlkes  9.2m HobbyEberly Telescope  2.7m Harlan J. Smith Telescope  2.1m Otto Struve Telescope  0.91m and 0.76m imaging telescopes

McDonald Observatory Overview  Located in the Davis Mountains of Far West Texas: a very dark continental site in the southwest United States at 2,040m elevation

McDonald Observatory Overview  West Texas is a large area of low population density  ~ persons per square mile  large cattle ranches: square miles each  McDonald likely to remain a dark site for the foreseeable future  But not without vigilance and care …  Davis Mountains are an increasingly popular vacation and retirement destination

Over the geographic area that impacts the observatory:  Eliminate the availability and use of poor quality, polluting light fixtures  Gradually replace poor quality existing lights, home by home, business by business, community by community Lighting Program Goals

Targeted all United States territory within ~ 100 kilometers of McDonald Targeted all United States territory within ~ 100 kilometers of McDonald  Jeff Davis, Brewster, Presidio, Pecos, Reeves, Culberson and Hudspeth Counties in Texas  Towns: Alpine, Marfa, Fort Davis, Presidio, Balmorhea, Van Horn Goal: Enact lighting ordinances in each of these counties and towns Goal: Enact lighting ordinances in each of these counties and towns

Lighting Ordinance Lighting ordinance goals Lighting ordinance goals  More efficient and attractive outdoor lighting  Improved visibility and security  Reduction of waste light  Elimination of glare and light trespass  Energy conservation  Dark night sky preservation

Lighting Ordinance Requires full cut-off fixtures for all new lights with an output > 1800 lumens Requires full cut-off fixtures for all new lights with an output > 1800 lumens Prohibits mercury vapor fixtures Prohibits mercury vapor fixtures Grandfathers existing fixtures Grandfathers existing fixtures  Goal: eventual replacement Restricts floodlight pointing Restricts floodlight pointing Allows only limited exemptions Allows only limited exemptions  Christmas Holiday decorations  Lighting required by law, e.g., air safety  Emergencies  Sports event lighting

Lighting Ordinance Must be politically salable at the local level, i.e., must be defensible as satisfying more than our need for dark skies Must be politically salable at the local level, i.e., must be defensible as satisfying more than our need for dark skies Seed funding for hardware purchases greatly elevates community interest Seed funding for hardware purchases greatly elevates community interest  McDonald funding sources have included Texas Star Party, Big Bend Astronomical Society, individual private donors, etc...

Public Education Must overcome public misunderstanding of the issues associated with lighting and astronomy Must overcome public misunderstanding of the issues associated with lighting and astronomy  Initial defensive posture  Overcome by concentration on the end-users concerns (security, visibility) rather than astronomy’s desire for dark skies 

 Consistently and proactively work with homeowners, businesses and governmental agencies  Persuade neighbors that non-polluting lighting is advantageous to them  Position funded by the Director’s Office to work with and talk to local communities Public Education

 As a net contributor to neighboring communities, McDonald gains good will and political capital  K-12 educational programs  K-12 curriculum-specific guided tours  Periodic, unique night- time observing programs open to all locals Public Education

The economic viability of cattle ranching has declined The economic viability of cattle ranching has declined  Ranchers face declining profits  Result: division of single, low occupancy, large tracts of land into numerous acre “ranch-ettes” Nature Conservancy of Texas has purchased several large Davis Mountains ranches Nature Conservancy of Texas has purchased several large Davis Mountains ranches  Resells some ranchland, but only in large tracts  Land deeds incorporate easements, including stringent lighting restrictions  100,000 + acres now protected in area surrounding McDonald Observatory Conservation partnership

State of Texas Support Texas Department of Transportation adopted full cut-off lighting standards for state highway lighting Texas Department of Transportation adopted full cut-off lighting standards for state highway lighting Texas House Bill 916 signed into law in May 1999 by then Texas Governor George Bush requires all state-funded lighting to be full cut-off fixtures Texas House Bill 916 signed into law in May 1999 by then Texas Governor George Bush requires all state-funded lighting to be full cut-off fixtures

Summary A balanced mix of A balanced mix of –public education –attention to the interests of the end-user –state-wide legislative support –collaboration with conservation organizations –dedicated observatory personnel –seed hardware funding has resulted in effective lighting ordinances being adopted by communities within ~ 100 kilometers of the McDonald Observatory protecting the dark West Texas night sky for the indefinite future