A Simple Streetlight Hack Could Protect Astronomy From Urban Light Pollution
upstart writes:
Light pollution is a growing threat to astronomy, but a new streetlamp technology could restore clear views of the night sky.
Light-emitting diodes (LEDs) consume only about 10% of the electricity required by traditional incandescent lights and last up to 25 times longer, so it's no surprise that they have become commonplace over the past two decades.
But there is a downside to LEDs: They're much brighter than old-fashioned energy-guzzling light bulbs. When an entire city gets fitted with energy-saving LED lamps, this bright light scatters through Earth's atmosphere and makes the sky glow with greater intensity.
[...] A study published earlier this year found that stars are disappearing from the sky at an average rate of 10% per year. This trend affects even the world's most remote observatories. Germany-based startup StealthTransit recently tested a solution to this growing issue.
"Unfortunately, this problem haunts almost all observatories today," Vlad Pashkovsky, StealthTransit's founder and CEO, told Space.com in an email. "Modern telescopes are highly sensitive and feel the impact of outdoor lighting of cities located at the distance of 50 or even 200 kilometers [30 to 120 miles]. This means that virtually every observatory on Earth either already needs, or will need in the future 10 years, protection from the light of large cities."
StealthTransit's solution relies on three components: A simple device that makes LED lights flicker at a very high frequency that is imperceptible to the human eye, a GPS receiver, and a specially designed shutter on the telescope's camera that can blink in sync with the LED lights. The GPS technology guides the telescope's shutter to open only during the fleeting moments when the LED lights are switched off.
The experiments, conducted at an observatory in the Caucasus Mountains in Russia, showed that the technology, dubbed the DarkSkyProtector, could reduce unwanted sky glow in astronomical images by 94%.
[...] It might sound impractical to refit an entire town with devices that allow lamps to blink, but Pashkovsky said that most existing LED lights can operate in the blinking mode and that new lamps designed specifically with sky protection in mind would be no costlier than existing LED technology. The most expensive element of the DarkSkyProtector system is the telescope shutter, which needs to be lightweight and agile enough to blink about 150 times per second.
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