Preserving Dark Skies: The Role of the Professional Astronomer Donald R. Davis & David L. Crawford International Dark-Sky Association Tucson, Arizona USA International Conference on Light Pollution IAU Commission 50 Working Group Conference La Serena, Chile, 5-7 March, 2002

The Role of the Pros Professional astronomers were the first to recognize the threat of artificial sky brightness or “light pollution.” Example: Steward Observatory and the electrification of Tucson in the 1920’s. Professional Astronomers spearheaded the first effective action to pressure dark skies through adoption of outdoor lighting codes and establishment of permanent, though voluntary, standing technical committees.

Activist Astronomers: Comparison with Other Populations Population of professional astronomers in the U.S. ~6,429 individuals of the AAS (6/30/01) Population of U.S. dark-sky supporters (IDA members) ~7,362 (7/01) Population of AAS astronomers who are IDA members ~295 (4.6% of AAS are also IDA members) Population of AAS astronomers who are active in preserving dark skies ~10 (0.2%) Population of the U.S. ~280,000,000 Fraction of U.S. population who are IDA members (0.003% of the total U.S. population) Population of amateur astronomers in the U.S. ~150,000 Population of amateur astronomers who are IDA members ~2,000 (1.3% of the amateur population)

So, professional astronomers support dark sky preservation at ~1500x the rate of the population as a whole and 3x the rate of amateur astronomers. Still, only ~5% of astronomers are involved! But this is up from three years ago when only ~2% of the AAS also belonged to IDA.

Observatory Support of Dark-sky Preservation Until recently, support of efforts to preserve dark skies by professional observatories has been rather haphazard. Much of the work [protecting the night sky for observations] for the large observatories has effectively been done...the problem of urban and highway lights encroaching on small optical observatories, including amateurs, is the main job in the future... Discussions at IAU Symposium 196 (Vienna, 1999) suggested that professional optical observatories should devote ~1% of their annual resources to preserving dark skies.

Recommendations for Professional Observatories from Preserving the Astronomical Sky IAU Symposium, Vol. 196, 2001 R. J. Cohen and W. T. Sullivan, III, eds. Astronomical support for the cause: We urge that astronomers and observatories work with and support those individuals and organizations involved in the protection of the dark skies. The new Commission 50 working group can be one of the mechanisms. Each observatory should have a light pollution officer as a point of contact. We urge all observatories to measure and monitor the sky brightness and other adverse environmental impacts at their observatories and we urge the IAU to set up a mechanism to coordinate such measurements.

Observatories/Astronomical Institutions that are IDA Members A) Lifetime Members 1) United States Naval Obs. 2) Cerro Tololo InterAmerican Observatory 3) Vatican Observatory Group 4) Kitt Peak National Observatory 5) California Association for Research in Astronomy 6) European Southern Observatory 7) Gemini Observatory 8) McDonald Observatory (Austin, TX) 9) United States Naval Observatory 10) National Radio Astronomy Observatory

Observatories/Astronomical Institutions that are IDA Members B) Annual Members 1) Anglo-Australian Observatory 2) Apache Point Observatory 3) Armagh Observatory 4) Center For High Angular Resolution Astronomy 5) Instituto de Astron. de Canarias 6) MMT Observatory 7) Mt. Wilson Institute 8) Smithsonian Astrophysical Observatory 9) Steward Observatory 10) Uttar Pradesh Obs.

Status of Light Pollution Activities at Major Observatories Observatory CommentThreat?LP OfficerResources CTIO/NOAO Yes Schwartz/Smith ~2% Whipple/MMTOAbsolutelyBrocious/Foltz~ 1% KPNO/NOAO Yes Green ~0.2% USNO (FLG) Yes Luginbuhl ~2% VaticanYesCorbally~ 3% SO/LBT YesSpitz<1% KeckYesLaub3% LP time McDonaldYesBash10K + 25% LP Status of Light Pollution Activities at Major Observatories Observatory CommentThreat?LP OfficerResources CTIO/NOAO YesH. Schwartz ~ 1% ESO ? USNO (Flagstaff)YesC. Luginbuhl ~ 2% KPNO/NOAO Yes Green <1% MMT/SAO Yes Brocious/Foltz <1% SO/VATT Yes A. Spitz <1% (Mt. Graham) C. Corbelly ~ 1% La Palma ~50 yearsJ. Diaz5-10% 2.5 people(Operations) Palomar ? CFHT/IRTF YesSalmon

Summary Most astronomical observatories are threatened with major increases in sky brightness in the next 25 years. The professional astronomical community must become more proactive in issues of how growth will impact dark skies. Work to develop allies, both locally and globally, among politicians, administrators, lighting professionals, etc. Everyone loves a starry sky. Build on that!

Specific Issues/Actions Data: Regular sky brightness measurements. Data: Analysis of existing global satellite measurements. Modeling: Improved tools for LP prediction. Analysis Center for LP. Resources: ~$100,000(US) /year. Potential sources: observatories, grants, lighting industry, environmental organizations.