¡SkyCaramba! Weekly astronomy blog for the week ending April 11, 2015
A lot of people, even a few who like astronomy, do something that’s harmful to it. Our modern lifestyles require outdoor lighting at night. Poorly chosen and poorly placed lights make it hard or impossible to see most of the stars in the sky. Many astronomy organizations have chosen the week of the new moon in April every year to be International Dark Sky Week. They want to promote respect for the darkness and keeping the light only where it’s needed.
No one is arguing against any and all outdoor lighting. Light the path to your door if you need to. We’re just asking anyone and everyone putting lights outside to consider how much light is really needed and where. Then choose the appropriate light fixture for the job.
A bare light bulb sends light in almost all directions. But does it need to? If your light is meant to show people where the sidewalk and steps are, you don’t need light shining toward the sky. If you need to light up the yard so you can see prowlers, several carefully placed dim lights will fill in shadows. But ...