Contrary to the opinion of many people, security is not proportional to the intensity of the security light outside their home. Well designed, well placed, lower power lights are just as effective. Advertise using billboards that have a dark background and bright letters, rather than a bright background and dark letters. If the background is dark, less light will be reflected from the billboard into the sky. Use low-pressure sodium lamps if possible.
Astronomers can use a filter on their telescopes to block that color of light.
The University of Texas at Austin McDonald Observatory Visitors' Information Center web site has a page on their Light Pollution Reduction Project.