To be honest, I thought about logging in to dublinelevation.net and designing a "dark sky sculpture" consisting of existing heavenly bodies (by turning all of the spotlights out!) I appreciate the fact that you do consider the impact of your art on nature. If skyword pointing lights used extremely narrow bandwidth light (e.g. laser or dichroic/interference filter), professional astronomers far enough away _might_ be able to work around the obstruction with expensive filters. But this would not solve the problem for ordinary people trying to enjoy the sky with their own eyes. Already few can see the beauty in the night sky that existed only a generation ago. For example, after a Los Angeles California earthquake cut power for a wide light polluted area, police were overwhelmed with telephone calls from people afraid of "strange lights in the sky." It was the milky way, something your grandfather would have known.
  