roof mounted white laser

Post Reply New Topic

Hi there! There's a beam of light coming off the roof of a tall building in Portland. Its orientation is horizontal to the north. I'm wondering if you knew what this might be?

It's been suggested that it might be an air quality monitoring system. My father says it's measuring the distance between the earth and the moon but it's not pointing up.

well were was the moon on its rise? or if it had not risen, perhaps it point to the horizon awaiting its rise.

more importantly, i love your signature. hilarious. dont change it.

Anything aimed "horizontal to the north" (90° to the equator) would not point at the Moon, since the Moon's orbit takes it no further north than 28.58° to the Earth's equator.

Likely, it is only a searchlight or a spotlight. Possibly a publicity stunt.

the weather monitoring stations we use for remote locations use infrared lasers (as far as i know white lasers are broad spectrum lasers and incredibly difficult to make and maintain)
they can measure airspeed at multiple altitudes as well as humidity and temperature, they are incredibly usefull as they can tell about wind layers in high lift zones that would otherwise be impossible to detect.

Google searches are leading me to believe it's a LiDAR system gauging air quality.

You could ask the Federal Aviation Administration. Lights and lasers have safety implications for aircraft, so are marked on aeronautical charts.

I don't think lasers can be white. Laser light is coherent, which means it must be monochromatic. White light is a mix of the whole spectrum hence not monochromatic.

A triple-mode laser can be made to emit red, green, and blue (RGB) light in the right proportions so as to appear white. Such lasers are expensive, and very rare for commercial or private use. An alternative would be to use three lasers (R, G, and B) and converge the beams through precision optics.

Is it there every night?
What building is it coming off of? (a short description will do)
Finding out a little about the building and who occupies it could explain a lot.
I'm also in Portland, I'd like to check it out.

on a foggy, rainy or snowy night, head south on 295 and you'll see it coming off the roof of the Glickman library (USM library - across from where Arbys used to be. Are they still open?)

Oh, wrong portland