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Optolong Pro and LED light Pollution

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#1 Marsman304

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Posted 09 March 2021 - 02:40 AM

Newbie here.  I read so much about how good the Optolong filters are.  I am in a Class 8 Bortle city.  I have been told by my local photography shop that the L-Pro will not make a difference in my city due to the heavy use of LED street lighting.  Can anybody verify this?  I seem to read a lot about people saying it works great for light pollution.  What is never clarified is whether it is LED lighting or Sodium lighting or some other type.  Any Help would be appreciated.  Thanks!



#2 imtl

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Posted 09 March 2021 - 02:50 AM

It's worthless. LED is broadband emission source.


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#3 CoHPhasor

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Posted 09 March 2021 - 02:51 AM

Filters like the pro, enhance, and extreme attenuate specific light wavelengths. (filters them out altogether)

Different lights are showering the sky at different wavelengths.
Which those are, for LED streetlights, I do not know.

What I can say for certain, is the usage of said filters depends on what targets you want to image.
("broadband" targets like galaxies are putting out lights out many frequencies and your images take a hit)
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#4 bobzeq25

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Posted 09 March 2021 - 03:10 AM

It's completely target dependent.  These filters do not magically know what light pollution is, the take a whack at it by blocking certain colors and letting others through.  The idea is that what they block is hopefully light pollution, and what they pass is target signal. 

 

That works pretty good with emission nebulae and metal vapor lights.  By the time you get to galaxies and LEDs, they're worse than useless.

 

Advice.  Use one on emission nebulae ONLY.  Even with LEDs that can work OK.  The best filters are NOT the LPro.  They're duo or triband filters like the LEnhance.  These are very popular, for good reason.  They pass most of the light from emission nebulae.

 

Another very useful tool is gradient reduction in processing, which also combats the effects of light pollution.  It's not perfect, but it uses spatial variation, not color.  Light pollution is a gradient, strongest at the horizon, least overhead.  So GR works on all targets and all sources of light pollution.  I strongly recommend it to you.

 

Processing programs that have good gradient reduction tools include Astro Pixel Processor (my top recommendation), PixInsight, and StarTools.  They're not free.  You spend thousands on the first half of imaging, data capture.  Spending a couple of hundred on the second half, image processing, is hardly extravagant.  "Free" options often are not free in terms of frustration and image quality.


Edited by bobzeq25, 09 March 2021 - 03:14 AM.

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#5 Marsman304

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Posted 09 March 2021 - 03:21 AM

Excellent...Thanks!  I guess I'm expecting too much from these filters.  I will take a look at the L-Enhance for emission nebula.  Since we are getting into Galaxy season, I just wasn't sure if it would be a benefit to give the L-pro a try.  Thanks for saving me money...lol.  

 

The software/processing part is a whole different ball game.  I have been using Deep Sky Stacker, Sequator (recently), and  Photoshop for all my processing.  I will take a look at Astro Pixel Processor as well.  PixInsight scares the hell out of me.  



#6 imtl

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Posted 09 March 2021 - 03:26 AM

PixInsight scares the hell out of me.  

Too bad, there is not real reason for that besides reading too many "I want a quick dirty picture now" posts on CN.

And even that you can get with PI, but you have other software that are free and more straightforward to achieve it as well.

You want to do imaging? put your efforts when you should


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#7 Marsman304

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Posted 09 March 2021 - 03:33 AM

Too bad, there is not real reason for that besides reading too many "I want a quick dirty picture now" posts on CN.

And even that you can get with PI, but you have other software that are free and more straightforward to achieve it as well.

You want to do imaging? put your efforts when you should

It is more about the terminology used in Pixinsight.  the processing part is a learning curve I'm not afraid of.  It just seems more complicated than PS.



#8 imtl

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Posted 09 March 2021 - 03:50 AM

Oh well. I tried :)



#9 awilliams

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Posted 09 March 2021 - 04:37 AM

Another very useful tool is gradient reduction in processing, which also combats the effects of light pollution.  It's not perfect, but it uses spatial variation, not color.  Light pollution is a gradient, strongest at the horizon, least overhead.  So GR works on all targets and all sources of light pollution.  I strongly recommend it to you.

 

I have a question about this, am I right in thinking that GR is not equivalent to a light pollution filter? The way I see it when you do GR you are removing the light pollution signal but leaving the noise from the light pollution so the SNR on your target is not effected. If you use a light pollution filter (assuming for a moment that it does actually filter the light pollution in question out) you are removing both the signal and the noise so in principal your SNR would improve.

 

As you say this is entirely dependent on your target and light pollution source if at least one of them has a narrow bandwidth then it will probably help otherwise probably not.



#10 CoHPhasor

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Posted 09 March 2021 - 04:51 AM

the LP filters attempt to stop the light pollution from being recorded by making the image be "blind" to certain bandwidths, which will also make you "blind" to the signal from the target on those same bandwidths.

The gradient removal attempts to reduce signal based on an assumed constant shift from one point to another.

#11 maxsid

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Posted 09 March 2021 - 05:15 AM

(of course L-eNhance and L-eXtreme are good since they are essentially narrow-band filters. Not LP filters)

 

I was reading about LP filters vs. no LP filters on these forums for some time.

Since we are polluted with broad-band LED light these times - L-Pro should be useless, right?

But, no.

Here's my two pictures. 

APP stack/stretch. No additional processing.

Bortle 8. With several LED street-lights around.

L-Pro is cleary better.

 

UVIR filter

2021-01-10-1-horse-uvir-mod--180degCW-1.0x-MNC-NS-St-reg-St-crop-sm.jpg

 

L-Pro filter

2021-01-10-2-horse-lpro-mod--180degCW-1.0x-LZ3-NS-St-reg-St-crop-sm.jpg


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#12 imtl

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Posted 09 March 2021 - 05:42 AM

First, looking at your examples, better in what way? Did you compare SNR? Did you stretch the same way? Did you do any background extraction?

 

With emission nebula (not HH which is not an emission nebula but background is), using a "narrowband" filter helps a lot. To improve contrast. That is irrelevant of LP. With those targets in question, I would pick the L-extreme 100 times over L-pro. (I actually do not use any of that since I shoot in mono setup).

 

Now run your L-pro on a broadband target and not the HH and let's see how it performs.



#13 F.Meiresonne

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Posted 09 March 2021 - 05:51 AM

Excellent...Thanks!  I guess I'm expecting too much from these filters.  I will take a look at the L-Enhance for emission nebula.  Since we are getting into Galaxy season, I just wasn't sure if it would be a benefit to give the L-pro a try.  Thanks for saving me money...lol.  

 

The software/processing part is a whole different ball game.  I have been using Deep Sky Stacker, Sequator (recently), and  Photoshop for all my processing.  I will take a look at Astro Pixel Processor as well.  PixInsight scares the hell out of me.  

L-enhance is pretty impressive on emission nebulae I learned sofar. They come at a price and I don't mean dollars or euros...but star colors. You will have to find a work around or take it as it is....


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#14 OrionSword

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Posted 09 March 2021 - 10:58 AM

Not all LED street lights are created equal.  There have been communities who first installed these with the blue/white spectra which are indeed more problematic for LP filters.  Some of these same communities which had a high rate of complaints because of the garish lighting effect in the area, ended up changing them over to warmer spectra and for these the LP filters can be more effective.  I've noticed some used in our city on the newer installations look more like the old sodium vapor spectra and also have excellent shielding.



#15 bobzeq25

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Posted 09 March 2021 - 10:59 AM

(of course L-eNhance and L-eXtreme are good since they are essentially narrow-band filters. Not LP filters)

 

I was reading about LP filters vs. no LP filters on these forums for some time.

Since we are polluted with broad-band LED light these times - L-Pro should be useless, right?

But, no.

Here's my two pictures. 

APP stack/stretch. No additional processing.

Bortle 8. With several LED street-lights around.

L-Pro is cleary better.

 

UVIR filter

attachicon.gif2021-01-10-1-horse-uvir-mod--180degCW-1.0x-MNC-NS-St-reg-St-crop-sm.jpg

 

L-Pro filter

attachicon.gif2021-01-10-2-horse-lpro-mod--180degCW-1.0x-LZ3-NS-St-reg-St-crop-sm.jpg

The LPro is not "useless".  (Ridiculously exaggerating what someone says is a common thing on CN.  In debate parlance it's a reductio ad absurdum argument).  It's just not as good as the LEnhance on emission nebulae.

 

And the key question is not whether a filter is good by itself.   It's, if you do gradient reduction, does a filter provide additional benefit?
 


Edited by bobzeq25, 09 March 2021 - 11:18 AM.


#16 bobzeq25

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Posted 09 March 2021 - 11:15 AM

I have a question about this, am I right in thinking that GR is not equivalent to a light pollution filter? The way I see it when you do GR you are removing the light pollution signal but leaving the noise from the light pollution so the SNR on your target is not effected. If you use a light pollution filter (assuming for a moment that it does actually filter the light pollution in question out) you are removing both the signal and the noise so in principal your SNR would improve.

 

As you say this is entirely dependent on your target and light pollution source if at least one of them has a narrow bandwidth then it will probably help otherwise probably not.

This is a reasonable argument.  Here's the thing.

 

Light pollution is, by any reasonable standard, "noise".  Like all noise in AP it has two components.  A fixed component (another word is offset), and a random component.  The random component is approximately the square root of the fixed component.

 

This is all well described in this superb book, with excellent bar charts.

 

https://www.amazon.c...h/dp/1138055360

 

Keeping the numbers simple.  Say the fixed component of light pollution noise is 100.  The random component will be about 10.  The total noise is 110.  A filter can attack the whole 110.  But gradient reduction can attack 100.  Not too shabby.  <smile>

 

Here's how it all shakes out.  Pretty much all serious imagers do GR on everything.  Some will add a light pollution filter, some won't.  Those who do generally add them on emission nebulae only.

 

My astrobin shows what can be done in light polluted skies.  Red Zone, Bortle 7, mag per arc sec squared low 18s.  Those images make little use of light pollution filters, I do some narrowband (sometimes combined with broadband) on emission nebulae.  Only.  Narrowband filters are usefully though of as light pollution filters that work, at the cost of totally unrealistic color.  The Hubble image of the Pillars of Creation is an excellent example.

 

Some people in Bortle 9 do little but narrowband images of emission nebulae.

 

 

 

 



#17 bobzeq25

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Posted 09 March 2021 - 11:24 AM

 

The software/processing part is a whole different ball game.  I have been using Deep Sky Stacker, Sequator (recently), and  Photoshop for all my processing.  I will take a look at Astro Pixel Processor as well.  PixInsight scares the hell out of me.  

PixInsight is not too scary.  But, if you're going to take advantage of it, it takes a lot of time.  I have hundreds of hours in learning and using it.  It takes me 10-50 hours to do an image.  In my best year I did 17.

 

You can usefully think of APP as "PixInsight Lite".  Mostly as good, far less time.  Time spent learning APP is not wasted if you later move to PI, most of what you learn will transfer, it's more adding things rather than replacing them.

 

If you decide to keep using Photoshop, there's a Gradient xTerminator add on that's very decent.  Not as good as others, it operates on stretched data, GR works better with linear data.
 


Edited by bobzeq25, 09 March 2021 - 11:25 AM.

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#18 Marsman304

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Posted 09 March 2021 - 01:23 PM

Oh well. I tried smile.gif

I'm not discounting it...just explaining my fears...lol



#19 Marsman304

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Posted 09 March 2021 - 01:35 PM

The LPro is not "useless".  (Ridiculously exaggerating what someone says is a common thing on CN.  In debate parlance it's a reductio ad absurdum argument).  It's just not as good as the LEnhance on emission nebulae.

 

And the key question is not whether a filter is good by itself.   It's, if you do gradient reduction, does a filter provide additional benefit?
 

Interesting....there is definitely a difference.  



#20 klaussius

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Posted 09 March 2021 - 01:38 PM

There's a new batch of light pollution filter designed specifically for LED lights.

 

What they do is they cut as much of the blue peak as possible without hurting the interesting bits of signal, but otherwise try to be color-neutral like the L-Pro.

 

Examples of these are the IDAS LPS D2 and the Orion 5561 imaging filter. I got me one of the latter but haven't had a chance to test it yet.

 

The L-extreme will leave them in the dust, but the L-extreme does nothing for galaxies and reflection nebulae. I'll try the Orion 5561 next time I try a broadband target and then I'l be a bit wiser, but my hope is that they should help with that intense blue light pollution coming from LEDs that has been driving me nuts.

 

I don't expect a world of difference, they're still broadband filters and will let in a lot of light pollution. But if they can help a bit with the blue, which has been rubbish lately every time I try to do RGB, I'll be happy for it.

 

So, as it has been mentioned, for emission nebulae go with something like the L-extreme. It's tough on color balance, but you'll love the amount of signal you'll get.

 

For broadband targets, though... either get a dark sky or maybe try one of these new filters. Don't expect a lot, but it may be able to help.


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#21 Marsman304

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Posted 09 March 2021 - 01:40 PM

PixInsight is not too scary.  But, if you're going to take advantage of it, it takes a lot of time.  I have hundreds of hours in learning and using it.  It takes me 10-50 hours to do an image.  In my best year I did 17.

 

You can usefully think of APP as "PixInsight Lite".  Mostly as good, far less time.  Time spent learning APP is not wasted if you later move to PI, most of what you learn will transfer, it's more adding things rather than replacing them.

 

If you decide to keep using Photoshop, there's a Gradient xTerminator add on that's very decent.  Not as good as others, it operates on stretched data, GR works better with linear data.
 

Thanks for the info.  Good to know about APP.  Would you recommend going straight to Pixinsight and just start the steep learning curve?  I have noticed in almost every astrophotographer I follow online, will also use Photoshop to finish the photos at the very least.  seems most use Photohop in tandem with one of the other processing software programs.



#22 Marsman304

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Posted 09 March 2021 - 01:43 PM

There's a new batch of light pollution filter designed specifically for LED lights.

 

What they do is they cut as much of the blue peak as possible without hurting the interesting bits of signal, but otherwise try to be color-neutral like the L-Pro.

 

Examples of these are the IDAS LPS D2 and the Orion 5561 imaging filter. I got me one of the latter but haven't had a chance to test it yet.

 

The L-extreme will leave them in the dust, but the L-extreme does nothing for galaxies and reflection nebulae. I'll try the Orion 5561 next time I try a broadband target and then I'l be a bit wiser, but my hope is that they should help with that intense blue light pollution coming from LEDs that has been driving me nuts.

 

I don't expect a world of difference, they're still broadband filters and will let in a lot of light pollution. But if they can help a bit with the blue, which has been rubbish lately every time I try to do RGB, I'll be happy for it.

 

So, as it has been mentioned, for emission nebulae go with something like the L-extreme. It's tough on color balance, but you'll love the amount of signal you'll get.

 

For broadband targets, though... either get a dark sky or maybe try one of these new filters. Don't expect a lot, but it may be able to help.

I will look into those filters more.  Thanks.  Anything that might help. 



#23 sn2006gy

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Posted 09 March 2021 - 01:47 PM

I've had good luck with the LPRO as a light filter - regardless of LED or Moon and still managing beautiful broadband images.



#24 bobzeq25

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Posted 09 March 2021 - 02:03 PM

Thanks for the info.  Good to know about APP.  Would you recommend going straight to Pixinsight and just start the steep learning curve?  I have noticed in almost every astrophotographer I follow online, will also use Photoshop to finish the photos at the very least.  seems most use Photohop in tandem with one of the other processing software programs.

Just a personal choice.

 

But I'd recommend starting with APP for one reason.  As a new astrophotographer you've got a ton of things to learn, and learning PI will take valuable time and effort away from that.

 

There's very little you can do in Photoshop that you can't do in PI.  Mostly what there is is at least somewhat artificial cosmetic stuff.  I use PI, exclusively.  Again, personal choice.

 

I would disagree about people mostly using PI to finish of PI images.  I don't know if that's true or not, if you look at all imagers.  I know it's not true at the highest levels.  The key point is that PI has an enormous number of highly adjustable tools.  It's correctly said that, if there are two ways to do something, PI will have four.  <smile>

 

You hear PI is the "best".  But it's only the best if you use its capabilities to the fullest.

 

Here's a good read.  The first 1/3 has very valuable stuff about data capture that you can use, right now.  The last 2/3 has the best noise reduction techniques I have ever seen.  It shows what it takes to get the most out of PI.  I have no clue how he invented that workflow.  But I use it to my benefit.  You will NOT be doing that in Photoshop.  <grin>

 

https://jonrista.com...duction-part-1/

 

If or when you decide to do PI, I strongly recommend this book.  Well organized, unlike most websites I have seen it builds in a logical stepwise fashion, not trying to do too much, too fast.

 

It's got enough info to make good images.  But it's not comprehensive.  There's only so much you can do with PI in 450 pages.  <smiling, but not kidding>

 

https://www.amazon.c...5/dp/3319976885



#25 Marsman304

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Posted 09 March 2021 - 02:15 PM

Just a personal choice.

 

But I'd recommend starting with APP for one reason.  As a new astrophotographer you've got a ton of things to learn, and learning PI will take valuable time and effort away from that.

 

There's very little you can do in Photoshop that you can't do in PI.  Mostly what there is is at least somewhat artificial cosmetic stuff.  I use PI, exclusively.  Again, personal choice.

 

I would disagree about people mostly using PI to finish of PI images.  I don't know if that's true or not, if you look at all imagers.  I know it's not true at the highest levels.  The key point is that PI has an enormous number of highly adjustable tools.  It's correctly said that, if there are two ways to do something, PI will have four.  <smile>

 

You hear PI is the "best".  But it's only the best if you use its capabilities to the fullest.

 

Here's a good read.  The first 1/3 has very valuable stuff about data capture that you can use, right now.  The last 2/3 has the best noise reduction techniques I have ever seen.  It shows what it takes to get the most out of PI.  I have no clue how he invented that workflow.  But I use it to my benefit.  You will NOT be doing that in Photoshop.  <grin>

 

https://jonrista.com...duction-part-1/

 

If or when you decide to do PI, I strongly recommend this book.  Well organized, unlike most websites I have seen it builds in a logical stepwise fashion, not trying to do too much, too fast.

 

It's got enough info to make good images.  But it's not comprehensive.  There's only so much you can do with PI in 450 pages.  <smiling, but not kidding>

 

https://www.amazon.c...5/dp/3319976885

Thanks...I'll take a look at these links.  Right now my processing has been very limited to "copying" what others are doing, not fully understanding what I am doing.  I just need to pick a took and jump in and figure it out.  APP sounds like a reasonable place to start...and they offer a 30 day free trial.


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