SPEAKER

 
Today's speaker was Keith Kruger on the topic of light pollution.  We have been adding lots of outdoor lighting for public spaces and private businesses.  Much of the lighting is unshielded and the light projected upward is wasted energy.  As lighting has become more efficient, it has also become more invasive. Unshielded lights lead to sky glow which negatively affects astronomy, invasion of people's homes via windows and negative effects on wildlife and human health. 
Keith gave a demonstration of the difference in an unshielded 40 watt bulb versus shielded one.
The solution is to allow only exterior lighting in which the light does not project above a 90 degree angle.  The Dark Skies Ordinance prescribes this but it is not easy to enforce.  Future progress will depend on public education efforts and local laws that require dark skies approved lighting.