Keeping Maine’s Sky Dark at Night

Have you seen the Milky Way recently? At a recent meeting with Rob Burgess of the Southern Maine Astronomers, the topic of the nighttime sky came up (not surprisingly!). I mentioned my childhood memories of being awestruck by the Milky Way at night and asked why I don’t see much of the Milky Way these days.

Rob explained that light pollution is the culprit. As artificial lighting increases light levels at night, smaller, fainter stars become more difficult to see.

Apparently, the orange glow I see to the west is the ‘light dome’ created by Lewiston. Similar domes exist over Portland and most other cities and well-lit areas. Near cities, cloudy nighttime skies are hundreds to thousands of times brighter than 200 years ago.

Unfortunately, this decline in truly dark nights affects more than just our ability to see the Milky Way and many stars. It also affects wildlife.

According to the International Dark Sky Association (IDA), artificial light at night has harmful, sometimes deadly, effects on wildlife. Nocturnal animals whose habits have evolved around cycles of light and dark for millennia are particularly affected by our brightly lit nights.

Prey that use night as cover are more vulnerable to capture. Nighttime glare can disrupt wetland frogs and toads that emit mating calls only at night, reducing reproduction. Bright lights also interfere with birds’ migration and disrupt insect food webs.

The good news is – there are simple changes we can make to reduce our impact on the night. The general principles are:

  • Light only what needs to be lit
  • Provide light only when it is needed
  • Make lights no brighter than necessary
  • Choose ‘warmer’ lamps for outdoors (<3,000 k)
  • Shield lights so light illuminates downward only

These principles argue for motion-activated outdoor lights of less than 3000 k. It’s now possible to purchase outdoor flood lights with motion sensors built into the light, so you don’t need to buy a new fixture to take advantage of motion-sensing technology.

I now have a motion-activated LED entry light, set to a ‘warm’ light (which draws less current). It works beautifully and gives the creatures of the night their privacy (as long as they don’t try to come up our front steps)!