[Michael Piziak]

Thought this would be of interest to those of you that do Astro Photography


Astronomers Join Forces to Push Back Against Satellite 'Pollution' Ruining The Skies

[AstroDave]

The last time I was shooting a comet, every other frame (~10-30 second exposures) had satellite trails in them.

This is basically another example of a "tragedy of the commons" (https://en.wikipedia.org/wiki/Tragedy_of_the_commons) i.e. exploitation of something that collectively belongs to everybody (a dark sky) but is over used/exploited by a few, with few, if any, immediate consequences.

As a radio astronomer, I have sworn off ever getting internet via such satellites. By some definitions, our internet is not adequate - we have DSL and get ~12 MBs download, but only 0.7 MBs upload. We are too far out in the boonies (just 6-8 miles from town/already existing cable, but past a lot of empty space) for cable.

[Ray Cox]

Light polution took away my view of the night sky many years ago.
Now sadly no matter which direction that I look all that I can see are the flashing red lights of wind turbines. I'm sure that there are younger people than I who have never experienced the beauty of a crystal clear night sky. Thats a tragedy

[Michael Piziak]

I seen a news segment where the city of Chicago has completely converted all their public street lights to LED lights. On the show, it was reported that it was an environmental win since the LED lights use much less energy and an added bonus is the lights are saving the city much money in electricity costs.


After I read the article I linked to, I see where these exact such LED lights are hated by astronomers as they produce much more light pollution....

[Michail_P]

Hopefully there are still some places where a crystal clear sky can be enjoyed. Not much can be done about those satellites, I’m afraid.

[AstroDave]

After I read the article I linked to, I see where these exact such LED lights are hated by astronomers as they produce much more light pollution....

An interesting problem, but solvable.

Here in Flagstaff (the world's first "Dark Sky City"), street lights are also being replaced by LEDs, but with the concern and help of the local astronomers, to both cut down on light pollution (aim those lights DOWN, not up!) and make sure the spectral characteristics of the light are pleasing to users (those on the streets at night) as well as astronomically-friendly (not so much blue light). The good lights cost somewhat more, but the cost was deemed appropriate here.

To some extent, astronomers prefer the old fashioned sodium vapor lights (the ones with the yellow cast, which give you a ghastly skin tone). Almost all the light from these is emitted in a very narrow spectral range, which can be filtered out with appropriate narrow-band filters, leaving most of the rest of the spectrum undamaged and the sky relatively dark at those non-sodium wavelengths.

Overall, the LED lights make about as much total light as do the sodiums. The biggest mistake most cities (and private citizens) make with lighting is not aiming at ALL down. When you fly over a city at night, all that light you see from the plane is aimed upwards! That is wasted light - it doesn't do any good at all for folks wanting to see what's going on on the ground/street! It's that upwards-going light that gets scattered all over the sky, in all directions, which is what astronomers hate!!!!!

[Bob 256]

It's definitely a problem that grows with population growth (more total lights). I live in what would have once been considered the country, but now the growth of population has converted my dark skies to hazy ones and even in the larger towns where one could at least see stars, they are starting to become invisible. I, however, have a summer getaway which is about 50 miles from the nearest "town", and there, I can still enjoy the night sky in all its splendor, something that's becoming a privilege rather than a gift.

Lighting manufactures really need to take into account where their products point as AstroDave has mentioned which is all the more important with LED lights since they can't be filtered out of astro-images the way arc lighting lends itself.

[StiffLegged]

In our part of the world the street lights are being changed to led down-pointing units as they become due replacing. We’re sure the old sodium units gave more light to the street, but did we want to live in orange half-light…?

[Wheatfield]

In our part of the world the street lights are being changed to led down-pointing units as they become due replacing. We’re sure the old sodium units gave more light to the street, but did we want to live in orange half-light…?

My city is converting over to LED street lights. One of the things I have noticed is how much closer to the city I have to be before I can see the glow from them. They are also brighter at street level than the old sodium lights.

[AstroDave]

One of the things I have noticed is how much closer to the city I have to be before I can see the glow from them.

That is probably a design effect. The older sodium lamps tend to have a bulbous glass enclosure, which may be almost half a hemisphere in shape. Unless the whole lamp is recessed deep within a case, that enclosure radiates all over the place, including at least somewhat upward.

The new LED lamps (at least the ones here) have a very flat emitting surface (i.e. the numerous individual LEDs that comprise the lamp are all in a plane), so they are much easier to shield from sending light out other than down - a small skirt around the edge works fine. As you approach and look at some of these lamps, you see absolutely no light until you are close to right underneath. And, then they are VERY bright! Much brighter than looking at a sodium bulb.

[Madaboutpix]

To my mind, light pollution - whether down here or up in the orbit - is so much more than just some sort of nuisance bugging a bunch of stargazers or astro photographers. It is one of the countless ways in which humans have changed Earth's environment so fundamentally in what is now called the Anthropocene that it surely needs a more holistic perspective to find sustainable answers. More sustainability in this sense would incidentally also spell good news for us photographers, I reckon.

[Thagomizer]

To my mind, light pollution - whether down here or up in the orbit - is so much more than just some sort of nuisance bugging a bunch of stargazers or astro photographers. It is one of the countless ways in which humans have changed Earth's environment so fundamentally in what is now called the Anthropocene that it surely needs a more holistic perspective to find sustainable answers. More sustainability in this sense would incidentally also spell good news for us photographers, I reckon.

Indeed; the disruption of migration and lifeways of birds, insects, and other night-active creatures is an important issue too. We're not the only inhabitants of this planet, but too often we act as if we are.

[Digitalis]

One astrophysicist also pointed out the increased number of satellites polluting the skies also hinders the detection of incoming asteroids, which are typically quite faint objects in the night sky.

[yucatanPentax]

One astrophysicist also pointed out the increased number of satellites polluting the skies also hinders the detection of incoming asteroids, which are typically quite faint objects in the night sky.

Oh dear! Hoping to live out my mortal coil before becoming an impact crater like Chicxulub!

[clickclick]

And, then they are VERY bright!

This is one of the things I'm really disliking about LEDs and how they are being used. I find they are often bright to the point of being overpowering. I don't know if it's people just buying too powerful a bulb, bad color balance - harsh blue/white, not the right fixture/installation or all of the above. One of my neighbors appears to have fitted LED bulbs into standard fixtures on either side of their front door. The intensity of the light that they admit at night is nuts. It's really harsh looking towards their house, and it's a decent distance off. Not only is it uncomfortable to look at, but it completely blows away your night vision. I much prefer the warm glow of a low output tungsten filament. Satisfies my caveman roots.