DIY LP spectrum analyzer

[benzomobile]

Hello to all.

Does anyone know if it is possible to create a spectrometer able to analyze the light spectrum of our night skies, to obtain a quantitative and qualitative picture of the level of light pollution of our observation site?
I found this article, but it was written in 2014 ...:

What's in the Light? Probing Around With My DIY Spectroscope

Thanks,
Joe 

[Thalestris24]

13 minutes ago, benzomobile said:

Hello to all.

Does anyone know if it is possible to create a spectrometer able to analyze the light spectrum of our night skies, to obtain a quantitative and qualitative picture of the level of light pollution of our observation site?
I found this article, but it was written in 2014 ...:

What's in the Light? Probing Around With My DIY Spectroscope

Thanks,
Joe 

Hi

There are options - see the forum's spectroscopy section

Also http://www.threehillsobservatory.co.uk/astro/spectroscopy_16.htm and http://www.rspec-astro.com/star-analyser/

Louise

 

[benzomobile]

Ah... Thank you, Louise!

Joe

[Tim]

For all things spectroscopy I usually seek out Jack Martin.

https://www.britastro.org/user/5979

HTH

[andrew s]

If you want a spectrum of light polltion, day or night sky you will need a slit spectrometer. This can be done quite simply as you don't have a small target to get on the slit. Robin's website has some examples you can make or buy.

Regards Andrew

[Merlin66]

Have a look at Samir's simple "shoebox" spectrograph.......

http://www.samirkharusi.net/spectrograph.html

 

 

[Thalestris24]

5 hours ago, benzomobile said:

Ah... Thank you, Louise!

Joe

Hi Joe

Sorry, I missed the bit about lp... I'm not sure how practical it would be to obtain a spectrum of night time skyglow - if that's what you mean? But one can analyse and compare the different types of lp sources eg: http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-light-pollution/

Louise

[benzomobile]

Thank you, Louise for your welcome interest

I know about the Flagstaff dark skies site. It is a good reference base - and there are others, to better understand the SLP phenomenon.

In fact, my aim is to analyze the night sky as a whole in order to trace the type and intensity of light pollution on the basis of its light spectrum.
I hope that an easy-to-make detector can be realized, using a camera in full spectrum mode for shooting, together with a software for recording the intensity-wavelength in a linear graphic mode.
I think that a spectroscope could be fine, with appropriate modifications.
We'll see ...

Ciao,

Joe

[Thalestris24]

35 minutes ago, benzomobile said:

Thank you, Louise for your welcome interest

I know about the Flagstaff dark skies site. It is a good reference base - and there are others, to better understand the SLP phenomenon.

In fact, my aim is to analyze the night sky as a whole in order to trace the type and intensity of light pollution on the basis of its light spectrum.
I hope that an easy-to-make detector can be realized, using a camera in full spectrum mode for shooting, together with a software for recording the intensity-wavelength in a linear graphic mode.
I think that a spectroscope could be fine, with appropriate modifications.
We'll see ...

Ciao,

Joe

Hi Joe

I'm not sure how easy/possible it would be to produce a spectrum from a diffuse source. I would imagine the spectral components of a night sky would depend largely on what is the dominant light source but clearly the general skyglow will be scattered light with an undefined(?) spectrum which will probably tend towards a broadband spectrum. If your lucky, the dominant light source would be yellow sodium light but these days it's likely a mix with a lot of white light. Looking out of my own window at night there are a mix of sodium and white light sources visible but the skyglow is a net effect of the whole city. I've been concerned recently about the introduction of LED lights in my city. It's already difficult to filter the lp and LEDs will probably just make things worse. .

Good luck

Louise

 

[benzomobile]

1 hour ago, Thalestris24 said:

Hi Joe

I'm not sure how easy/possible it would be to produce a spectrum from a diffuse source. I would imagine the spectral components of a night sky would depend largely on what is the dominant light source but clearly the general skyglow will be scattered light with an undefined(?) spectrum which will probably tend towards a broadband spectrum. If your lucky, the dominant light source would be yellow sodium light but these days it's likely a mix with a lot of white light. Looking out of my own window at night there are a mix of sodium and white light sources visible but the skyglow is a net effect of the whole city. I've been concerned recently about the introduction of LED lights in my city. It's already difficult to filter the lp and LEDs will probably just make things worse. .

Good luck

Louise

 

I agree with you, of course.

Thus, different sites in different countries display different quantity, quality and pattern of light pollution reality.

Unfortunately the future does not appear rosy, because the new light sources based on the latest generation LEDs, show an almost continuous light spectrum, from deep blue to red.

My personal interest points  to evaluate  (my) specific  sky conditions in relation to that of sky in some reference sites, reasonably free from light pollution, in order to find a temporary solution to this problem, identifying the best possible filtration profile. This is also for the purpose of a personal study.

That's all :-)

So long,

Joe

 

[benzomobile]

P.S. This type of study had been done on the Los Angeles sky in the late 1980s, after the introductione of HPS bulbs in street lighting.

I have to find  that chart  (I suppose many of us who are over 50 should remember it).

BTW, this is an Cristian Buil interesting article:

http://www.astrosurf.com/buil/pollution/measure.htm

and, in English:

http://www.astrosurf.com/buil/filters2/compa.htm

Joe

[Thalestris24]

14 minutes ago, benzomobile said:

I agree with you, of course.

Thus, different sites in different countries display different quantity, quality and pattern of light pollution reality.

Unfortunately the future does not appear rosy, because the new light sources based on the latest generation LEDs, show an almost continuous light spectrum, from deep blue to red.

My personal interest points  to evaluate  (my) specific  sky conditions in relation to that of sky in some reference sites, reasonably free from light pollution, in order to find a temporary solution to this problem, identifying the best possible filtration profile. This is also for the purpose of a personal study.

That's all :-)

So long,

Joe

 

TBH it's probably not worth the time and effort to mess about trying to acquire a spectrum. There are only a limited number of good quality lp filters anyway, plus narrowband filters. If you have a lot of LED blue light then the idas d2 might help (I've no experience of using it myself). You can tell pretty quickly by taking exposures with a dslr or osc and looking at how the levels for r, g and b appear. APT displays that on-screen and that is echoed in the levels shown in dss after you stack. You can tell how dark your sky is with a meter, and it's probably obvious from looking at the sky by eye, and also from exposure times, whether your skyglow is bright.

Louise

[benzomobile]

11 minutes ago, Thalestris24 said:

TBH it's probably not worth the time and effort to mess about trying to acquire a spectrum. There are only a limited number of good quality lp filters anyway, plus narrowband filters. If you have a lot of LED blue light then the idas d2 might help (I've no experience of using it myself). You can tell pretty quickly by taking exposures with a dslr or osc and looking at how the levels for r, g and b appear. APT displays that on-screen and that is echoed in the levels shown in dss after you stack. You can tell how dark your sky is with a meter, and it's probably obvious from looking at the sky by eye, and also from exposure times, whether your skyglow is bright.

Louise

Yep, idas d2 might help against leds, but I've read recently the b2 one (I'm an owner of it) is still not worse,  also in polluted suburbs ...

Ok Ok,  full stop 

Joe