Light pollution concerns at FLWO

We post here information and news regarding our activities to protect the night sky. If you have questions or suggestions, please contact Dan Brocious or Emilio Falco at FLWO.

Increases in light pollution are inevitable in southern Arizona, as population grows. The area surrounding FLWO in Pima and Santa Cruz County is protected by reasonable outdoor lighting codes to minimize the impact of light pollution on astronomical research and on the experience of the night sky for everyone. However, our vigilance is essential to ensure that light-pollution is minimized.

A view from the summit (click image to magnify to 2Kx400 pixels). Landmarks, settlements and developments are marked. Note: The VERITAS site is no longer as indicated in this image.

A recent view of lights near FLWO.

A satellite view of light pollution in Southern Arizona.

A good example of light pollution under control in Monte Patria, Chile, 60km south of CTIO, before and after switching (in 2005) from mercury vapor to low-pressure sodium street lights. (Reference: Physics Today, June 2005.) Note: per Arizona Revised Statutes 49-1104, mercury vapor lights are not allowed in Arizona.

The following text documents events of interest, starting in 2004.



        AR continues promoting its Rosemont mine project.


            The Rosemont DEIS was released in October 2011. CNF is accepting comments until 01/31/12. We submitted comments
            expressing  our strong concerns about the incomplete outdoor lighting model for the mine, and about the lack of
            an analysis in the DEIS of the impact of dust. We also pointed out that the Smithsonian Institution and CNF entered
            into an Interagency Agreement under which the Forest Service will:

            "exercise administrative responsibility to protect and manage the multiple resources of the national forest lands within
            and adjacent to the Withdrawal in a manner compatible with the instrumentation tolerances and requirements of
            the Observatory as determined in consultation with Smithsonian."

            Although we stated our requirements in our comments as a cooperating agency from the beginning of the EIS process,
            these are not adequately reflected in the DEIS.
            CNF is processing the comments it received by 01/31/12 (over 10,000). We will continue to   
            work with CNF and its consultants SWCA to determine the amounts of dust and light emission from the mine, and will
            seek to include appropriate mitigation measures in the final EIS. The timeframe for CNF to arrive at a
            Record of Decision is unclear at the moment.
             In November 2011 the AZ Court of Appeals ruled that electronic billboards along state and federal highways
             violate the AZ Highway Beautification Act's ban on intermittent light. However, the AZ legislature is considering HB 2757,
             which amends sections 28-7902 and 28-7903 of the AZ Revised Statutes, adding:
                E.  Outdoor advertising authorized under this section may include billboards that are capable of changing messages                    
                mechanically or electronically by remote or automatic means if each static message displayed remains fixed for at least                
                eight seconds.
            This sentence allows LED billboards, which are extremely bright and whose light carries for very long distances,
            as shown in the recent paper by Walker et al. and as discussed here. See a summary for additional information on the noxious
            impact of LED billboards.
            AZ Governor Jan Brewer vetoed HB 2757 on 03/29/12. Her veto letter indicated her main reason was to defend the astronomy
            industry in Arizona. Thanks are due to many astronomers in Arizona, especially Jeff Hall (Lowell) and Buell Jannuzi (KPNO) for
            leading the push to inform the public and the legislature. The veto letter stated that the governor wished to encourage the
            astronomy industry and outdoor billboard companies to reach  a compromise. Such compromise was impossible for HB 2757.

            A new bill, HB 2543, is headed for final votes in the AZ legislature as of 04/26/12. It includes a compromise that will protect
            the observatories in Arizona, mainly by creating exclusion circles around the observatories, and restricting electronic
            billboards to an area that includes Phoenix, where about 70 such billboards are already in place. We will post the text here
            as soon as the bill is approved.

            On March 1, Falco, Brocious (FLWO) and Williams (MMT) met with the FS consultants (SWCA) and reps from Monrad lighting
            and other parties such as IDA. We discussed the new Monrad plan, which is a great improvement over the previous very poor
            scheme. We now await a model for the increase in sky brightness from Dark Sky Partners (DSP), which produced the estimates
            in the DEIS.