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Controlling Light Pollution (1Mar96) (from CTIO, NOAO Newsletter No. 45, March 1996) Although Cerro Tololo and Cerro Pachon are still very dark sites, CTIO has become increasingly concerned in recent years with the growing threat of light pollution from neighboring cities and towns. Thus we have begun to collaborate with local officials as well as private industry to insure that future lighting installations are as "astronomy-friendly" as possible. This program is being carried out on several different fronts. Public Information One of the basic problems facing us is a lack of awareness of the damaging impact of light pollution on astronomy. The people of the Fourth Region of Chile are very proud of the presence of Cerro Tololo and the other astronomical observatories in this area--indeed, Cerro Tololo has long been one of the most popular tourist destinations in this part of Chile. We have found that once the problem of light pollution has been explained, local officials, merchants, and residents have been quite willing to work with us to improve lighting standards. To reach even more people, we have provided information and interviews to local and national newspapers and television stations and given talks to various civic groups to publicize the problem. We plan to continue our efforts in this area during FY 1996 with the organization of a symposium in La Serena for businessmen and local government officials designed both to explain the problem and to provide practical solutions that will benefit everyone. Street Lighting Installations in Local Towns As part of a nation-wide program sponsored by Chile's National Energy Commission, the cities of Vicua and La Serena have embarked on a project this year to replace their old, energy-wasteful mercury vapor street lights with more efficient high-pressure sodium lighting. Although we would have preferred that the local towns adopt low-pressure sodium lights, this is not practical due the lack of suppliers in Chile. However, much can still be gained by replacing the old mercury vapor fixtures with fully-shielded high-pressure sodium lights. Vicuna (pop. 15,000) is the closest (12 miles) town to Tololo, and therefore potentially one of the most serious concerns for the Observatory. Fortunately, the town leaders have shown considerable interest in working with CTIO to improve existing street lighting, and to insure that future lighting installations are "astronomy-friendly." On their own, they contacted CTIO in the early stages of their project to seek advice on how best to insure that the new street lights would not significantly affect the telescopes on Tololo. This was just the opportunity that we had been looking for to work with a local town on implementing lighting ordinances that would more effectively control the problem of light pollution. Hence, CTIO has been providing the necessary technical assistance to the Vicuna city officials to insure that the change from mercury vapor to high-pressure sodium lights is carried out in a cost-effective manner that will result in better street lighting for Vicua and lead to an actual decrease in the light pollution affecting Tololo and Pachon. The successful completion of this project will serve as an important example to the other neighboring communities. Already, as a result of the publicity surrounding the Vicuna project, the city of La Serena (pop. 120,000) recently opted to install "astronomy-friendly" lighting as they also replace their old mercury vapor lights with high-pressure sodium. In this case as well, we have worked directly with city officials to insure that they have technical assistance necessary to achieve this goal. Light Pollution Ordinances City officials have told us that it would be easier for them to work with us in controlling light pollution if there were a national or regional norm for nighttime lighting that dealt specifically with the problem. After consulting members of both the executive and legislative branches of the Chilean government, we were advised that the best approach would be to work through the newly-created Comision Nacional de Medio Ambiente (CONAMA), which has been charged with creating and monitoring environmental law in Chile. Hence, we are presently working with the Director of the Fourth Region CONAMA office on a draft of an environmental norm aimed at controlling light pollution in the vicinity of the existing astronomical observatories in Chile. We have been very pleased with the support for this project shown by the CONAMA officials, and have been told that there is a good chance that this might be one of the first environmental norms to be considered by the Commission. We are currently working to finish the draft norm (which is modeled after outdoor lighting standards in Hawaii and the Canary Islands) so that it can be submitted to the CONAMA before the end of January. Once approved, the next step will be to work with the individual cities to create lighting ordinances that are consistent with the general specifications of the CONAMA norm. Mark Phillips, Ricardo Schmidt
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