The LED revolution is in full swing! Seems everyone is switching from whatever (incandescent, halogen, fluorescent, etc.) to LED. Why not, they save money, produce little heat, and last a long time. Oh, and the others are either out or on their way out of the manufacturing arena.
LED is our future.
But be careful. LED has one very negative attribute that seems to escape notice. Without filtering, LED light contains a lot of blue and blue light gets dispersed by the air, the same process that makes a sunny sky appear blue. This scattered blue light contributes to light pollution even when the light fixture is pointed downward!
In recent years cities around the country have been transitioning from sodium or mercury street lighting to LED. Hey, it saves the city a bucket of money and we all know cities struggle with budgets. Many cities were sold a promise of “Night Sky Friendly” LED street lighting. Yes, the fixtures point downward, and the LEDs do not extend physically beyond the fixture housing. So that is night sky friendly, yes? Not necessarily so. When you get around at night check out streetlights. Notice if they shine brightly white. That white light has a lot of blue! Notice that even though the light lens is flush with the housing bottom there can be a strong glare visible from the side. That’s the magic of mirrors! Unfortunately, that also contributes to the graying of our night sky.
That’s just one example, and cities are trying to do the right thing. What to do when we just want to put up security lights and don’t know kelvins from watts? Get help!
Locally there are several groups with folks at the ready to help you get control of your outdoor lighting, so you are not contributing to the problem of Gray Sky at Night.
Comal County Friends of the Night Sky: comaldarksky.org
The Hill Country Alliance: hillcountryalliance.org
Texas Chapter of the International Dark Sky Association: idatexas.org
If you feel intimidated by websites, here are basic recommendations:
–If you don’t really need to have the light on outdoors, keep it off. Otherwise…
–Pick LED bulbs with a 2700 K (Kelvin) or lower color temperature. They have a warm glow.
–Use the lowest watt bulb that satisfies your need.
–Point and shield the bulb so light only goes where it is needed and has no sideways glare
–Use a motion detector to turn the light on only as needed.
Night sky friendly fixtures can be found at Lowes, Home Depot, some ACE stores, and online vendors.
What’s in the Sky?
Tye Preston Memorial Library and the New Braunfels Astronomy Club kicks off fall Astronomy Night season on October 1st, 8:30 pm. It’s International Observe the Moon Night so please join our Moon gazing festivities.
September 22, 8:04 pm CDT: Welcome the autumnal equinox, it’s fall baby!
Saturn and Jupiter rule the night. Mars rises around midnight.