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The end of LP filters?


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Slightly off topic but would it be possible to use some kind of software to sample the offending lights and subtract from image capture ? A bit like darks and flats ?

Mmmmmm maybe something to try in DSS as it's now open source .

Edited by knobby
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With the increasing deployment of LED streetlights might it no longer be possible to use a lp filter of the kind that mostly works by cutting out the yellow sodium lines to reduce lp? Glasgow, where I

I used to work for a company as a physicist developing large area lighting panels, and the principle behind the majority of white LEDs is you use a blue LED diode and a yellow phosphor to achieve a wh

The new IDAS D2 filter has been made with LED lights in mind. If you follow the link below, you'll see that they have manged to filter out pretty much all of the "blue" peak, and some of the phosphore

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3 hours ago, fireballxl5 said:

but very useful info.

Is some body in the UK learning lessons from this kind of experience to determine policy for the UK's move to LED?

Do the CPRE/IDA use this kind of info to try and influence local councils who are rolling out LED street lighting?

CS, Andy

 

Hi

Unfortunately I don't think there is... I suspect changes to LED are largely driven by long term cost savings. I will write to my local authority and see what they say.

Louise

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1 minute ago, knobby said:

Slightly off topic but would it be possible to use some kind of software to sample the offending lights and subtract from image capture ? A bit like darks and flats ?

Mmmmmm 

Well the idas d2 filter purports to cut the blue end of the led light but essentially white LEDs are a broadband source.

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2 hours ago, Stu said:

Louise, I do hope the situation turns out to be better than you had hoped. I can only echo PeterWs comments in that they have improved the situation around here. My back garden used to be between mag 18 and 18.5, now it is generally high 18s, at best around 19.2 ish if I remember correctly, certainly above 19. They dim later at night which does help too. They are generally much better shielded and directed, reducing upward

Dont give up, hopefully things will improve. Well worth exploring some of those filters too. I know it is inefficient but is it even possible to consider narrowband imaging with a DSLR??

Yeah, I have done some imaging in Ha but even a 3.5nm filter still passes some skyglow. It may be worth experimenting with a combo idas d2 and a 3.5nm Ha and a cooled mono 4/3 cmos. I live in a red zone. Nothing's going to change that!

Louise

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Although the new ones are way better cutoff than the existing ones I would have gone for even more aggressively cutoff ones... what area does a light NEED to illuminate... right, stop it lighting up anywhere else... maximise the efficiency of the photons it produces. Why can I see dazzling little lights all into the distance?! People seem to want to be dazzled, proof that the councils are using photons to push the crime away. Much crime happens in the day when people are at work. Daylight can’t be as effective as streetlight as crime repulsion?!

i was pleasantly surprised when we stayed out “too long” at a club session and most of the streetlights had gone off when we packed up.

PEter

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I did a quick test last night on the new D2 IDAS filter versus the P2 and no filter at all. To me it looks like the D2 allows more green to pass but otherwise not much different to the P2 but the overall background colour looks better. The shot without any filters shows much more red passing. I used my Canon 1200d modded camera but these were only 15 second exposures at 800 ISO. Not very scientific but I like the colour balance better with the D2. The first is with the D2, the second is without a filter at all and the third is with the P2. I should point out that we have LED lights in the village but a close by village has sodiums.

Peter

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Driving at night I now wear night driving glasses or have the sunblinds down as much as on a bright day. The intense brightness is as dazzling as an oncoming driver with lights on full beam. One of those tinted tacky stick on strips is going to be needed. 

With respect to light pollution, the expensive Japanese filters FLO sells only mention benefitting imaging. Do they make any difference to visual?

The future of beating light pollution is electronic. Digital cameras already have filters, hopefully one day an off-the-shelf affordable gadget will be invented to help visual observers as well. 

Edited by 25585
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I live in Bushey Hertfordshire, bortle 6 zone, and I have London in the south east. I'm using a idas d1 filter but it only cuts some of the light pollution. Do you guys think a D2 would help a little more against the London's nightmare LP when imaging targets in the SE and S?

I took some images of the Rosette nebula using a 6nm Ha filter and you can see how the light pollution is decreasing as the target is drifting towards the SW during the imaging session.

Emil

Edited by emyliano2000
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47 minutes ago, emyliano2000 said:

I live in Bushey Hertfordshire, bortle 6 zone, and I have London in the south east. I'm using a idas d1 filter but it only cuts some of the light pollution. Do you guys think a D2 would help a little more against the London's nightmare LP when imaging targets in the SE and S?

I took some images of the Rosette nebula using a 6nm Ha filter and you can see how the light pollution is decreasing as the target is drifting towards the SW during the imaging session.

Emil

Hi

I can empathise though I'm probably about Bortle 8 :'(. I don't think anyone can tell you - the D2 is designed to cut blue light from LED lights. You would probably be best to avoid targets in the S, SE, if you can. Narrowband imaging certainly helps but LP is a scourge!

Louise

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Here in SW London LP is horrendous and still orange mainly from lp sodium on main roads with broadband fluorescent in residential roads to lesser extent but then I gave up eyeballing years ago in favour of brief exposure imaging to laptop in near realtime so I'm happy :-)

Nytecam

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My town also started to switch to LED streetlights. Can't say I'm a fan of them, the light is quite harsh compared to the softer glow of HPS. An additional problem with LED streetlights, is that depending on who makes the LEDs that go in them the spectrum they emit could differ, so even if a particular filter works on some LEDs, it may not work on others. Cheaper "white" LEDs tend to emit more blue light, which has negative effects on human night vision.

Sadly, I don't think they're going to stop replacing HPS with LED. Governments love shaving off every penny, and the potential cost savings switching LED are too good to pass on. 

Miss the good days of LPS, monochrome light is so much easier to deal with. 

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13 minutes ago, Garbus said:

My town also started to switch to LED streetlights. Can't say I'm a fan of them, the light is quite harsh compared to the softer glow of HPS. An additional problem with LED streetlights, is that depending on who makes the LEDs that go in them the spectrum they emit could differ, so even if a particular filter works on some LEDs, it may not work on others. Cheaper "white" LEDs tend to emit more blue light, which has negative effects on human night vision.

Sadly, I don't think they're going to stop replacing HPS with LED. Governments love shaving off every penny, and the potential cost savings switching LED are too good to pass on. 

Miss the good days of LPS, monochrome light is so much easier to deal with. 

Commiserations! But it must be open for people to complain - as they did in the case of Davis, California. I've written to my local city authority asking for details of their plans and pointing out the problems of harsh, blue-rich LEDs, but I've not had a reply yet. They intend to replace 60,000 street lights with LEDs....

Louise

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