Things Are Looking Brighter! But Not The Stars

Growing up in Montana I remember looking out at night and seeing the Milky Way, reminding me of my insignificance in the universe. Now that I live in a city, such introspection is no longer easy, and like 1/2 of humanity that also lives in urban areas, I must rely on satellites to provide the imagery. Yet satellites are part of the problem. Light pollution has been getting worse for decades, and with the recent steady stream of satellite launches and billionaire joyrides we have a relatively new addition to the sources of interference. So how bad is it, and how much worse will it get?

Looking up at the night sky, you can usually tell the difference between various man-made objects. Planes go fairly slowly across the sky, and you can sometimes see them blinking green and red. Meteors are fast and difficult to see. Geostationary satellites don’t appear to move at all because they are orbiting at the same rate as earth’s rotation, while other orbit types will zip by.

SpaceX has committed to reducing satellite brightness, and some observations have confirmed that new models are a full magnitude darker, right at the threshold of naked-eye observation. Unfortunately, it’s only a step in the right direction, and not enough to satisfy astronomers, who aren’t looking up at the night sky with their naked eyes, naturally.

The satellites aren’t giving off the light themselves. They are merely reflecting the light from the sun back to the earth, exactly the same way the moon is. Thus something that is directly in the shadow of the Earth will not reflect any light, but near the horizon the reflection from the satellites can be significant. It’s not practical to only focus our observatories in the narrow area that is the Earth’s shadow during the night, so we must look closer to the horizon and capture the reflections of the satellites. Continue reading “Things Are Looking Brighter! But Not The Stars”

Hacking A Streetlight With Lasers

$20, some spare parts and a bit of mischief was a small price for [Chris] to pay for a reprieve from light pollution with this remote control laser hack. The streetlight in front of his house has a sensor that faces westward, and flips the lamp on once the sun has disappeared over the horizon. As it turns out, [Chris’s] third floor window is due west of this particular lamp, meaning he takes the brunt of its illumination but also conveniently places him in a prime location for tricking the sensor.

According to [Chris], the lamp’s sensor requires two minutes of input before it will switch off and stay off for around 30 seconds before cycling on again. The lamp does not zap straight to full brightness, though; it takes at least a minute to ramp up. [Chris] recalled a hack from a few years ago that essentially used LED throwies tacked onto the sensors with putty to shut off lamps for a guerrilla drive-in movie, but the sensors on those lamps were at the base and easily accessed. [Chris] needed to reach a sensor across the block and nearly three stories tall, so he dug around his hackerspace, found a 5V 20mA laser diode, and got to work building a solution.

[Chris] 3D printed a holder for the laser and affixed it via a mounting bracket to the wall near his third floor window, pointing it directly at the street lamp’s sensor. He plugged the laser’s power supply into an inexpensive remote control outlet, which allowed him to darken the street lamp at a touch of a button. This is certainly a clever and impressive hack, but—as always—use at your own risk. Check out a quick demo video after the break.

Continue reading “Hacking A Streetlight With Lasers”