New Light Pollution Filtration Systems

[glend (Glen)]

I ran across this article claiming that LED lights can be filtered out of telescopes, published in Space.com


https://www.space.com/astronomy-ligh...reetlight-hack

Being honest I cannot see how it could possibly work, as individual LED lights are not in phase with one another normally. Certainly from Grid to Grid, phase lock is not possible in my view.
If anything this if it works, is a masking technique which would increase exposure time required for the special, ie expensive new cameras required. It does nothing about Starlink and other Sat pollution.

Comments?

[multiweb (Marc)]

I noticed that my area got so much brighter when they swapped all the street lights to white leds. It was so bad that I started doing planetary instead and I got new sets of filters with different bandpass in the UV and NIR from Edmund optics. They're costly but if you get small diameters they become more affordable. Some are very dense but by stacking a few of them you can completely block led lighting. Problem is that you dramatically need to increase integration time to let any star light through. I'm still working on combinations of filters. No problems with darks and bias frames but flats can also be challenging.

[Leo.G (Leo)]

Back in the 60s annoying street light shining in the bedroom at night were dealt with using a 22 or a sling shot. Eventually the council stopped fixing the things (I was a kid and didn't do it)

We can't legally own either now I believe.....
My street LED opposing my driveway lights up my back yard like a Friday night football game at any major oval.


Maybe I could bend some round bar, use a resistance band and a good ball bearing............

[Startrek (Martin)]

Glen,
I can’t see how this could work either ?
Sydney’s Skyglow has increased substantially since the introduction of LED lights around 15 years ago. You can see it in your subs when you compare year to year
Here’s my backyard on a typical night in Sydney’s burbs.My neighbours must have a fear of the dark or something ( and their not even in the backyard when the floods are blasting their yard and mine as well ) rank stupidity !! There’s these devices called motion sensors and time clocks to enable folk to control the use of artificial lighting. Obviously the contractor who designed and installed their exterior lighting was totally out of his depth. All my exterior lighting ( no massive floods ) are controlled via sensors and they were installed 35 years ago. I care about the environment and my neighbours.
And yes, I dare not approach them as they don’t care and Ive have had other issues with them in the past . I just put up with it and work around it with Bunnings poly tarps. Narrowband filters are my friend
Light pollution map had my area as Bortle 7 back in 2015 , it’s definitely now Bortle 8.
I do grumble from time to time but very fortunate to have a holiday retirement home on the South coast NSW with my NexDome under Bortle 3 skies.
Another kick in the butt if you live in Sydney will be the new Western Sydney Airport when it opens in 2026 with up to 180,000 flights per annum. No Astro algorithm can mitigate aircraft light trails and it will affect some folk depending on your location and imaging target path.
Our hobby is continually confronted and challenged with development in the big Cities.
Rant over ……..

[glend (Glen)]

Originally Posted by Leo.G

Back in the 60s annoying street light shining in the bedroom at night were dealt with using a 22 or a sling shot. Eventually the council stopped fixing the things (I was a kid and didn't do it)

We can't legally own either now I believe.....
My street LED opposing my driveway lights up my back yard like a Friday night football game at any major oval.


Maybe I could bend some round bar, use a resistance band and a good ball bearing............

I have heard of success being achieved by remote control drones carrying spray paint, or water based paint bombs in balloons. Very quiet and no danger of stray ball bearings flying around. Not that I would encourage that.

If we could get Alex to put up an accommodation block on his property, I am sure there would be a steady stream of bookings.

[Leo.G (Leo)]

Martin are you sure that isn't a sports oval?
Wow, that's a massive lumen output from security lights.
I have the automatic LED security lights in my backyard which on windy nights will continually be set off by cats and other movement in my back yard (a tarp over a tent) but if I notice them constantly I turn them off, as I do when I go out at night with a scope or camera.


Glen that's an interesting concept and no, I'm not stupid enough to risk ball bearings flying through an elderly neighbours window but I could build a rail gun, decidedly more accurate?
An interesting mention from a long time online friend who lives in Arizona, he has a laser set up on the roof of his house directed at a sensor on the street light outside his home, he says the light hasn't turned on in years. Though he no longer has an observatory but he says he likes the lights off when he has pool parties and just generally trying to sleep.


Do our lights have any such sensor over here?
I'm sure I could re-purpose a laser I'd have laying around somewhere.
Not my green lasers, that would be too obvious though I'm guessing even red would be considerably noticable in fog?