Light pollution and imaging time

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Light pollution and imaging time

Postby mechanoid » Sun Dec 02, 2018 12:49 pm

I've heard it said many times that you need longer exposure times to improve the signal to noise ratio in light polluted areas, but I don't see why.

When the noise source is random, the longer exposures dramatically improve the SNR because the noise level only increases as the square root of the total exposure time. So four times the exposure doubles the SNR.

But surely this doesn't hold for light pollution, which is not random. Doubling the exposure time just doubles both signal and noise, and gets you nowhere with regard to the light pollution component.

It seems to me the only way to deal with light pollution is to filter it optically, or find darker skies !

Can someone convince me that I'm wrong ?

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Re: Light pollution and imaging time

Postby paraman » Sun Dec 02, 2018 1:29 pm

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Re: Light pollution and imaging time

Postby carastro » Sun Dec 02, 2018 8:36 pm

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Re: Light pollution and imaging time

Postby mechanoid » Tue Dec 04, 2018 7:19 pm

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Re: Light pollution and imaging time

Postby Bill55 » Tue Dec 04, 2018 8:50 pm

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Re: Light pollution and imaging time

Postby mechanoid » Wed Dec 05, 2018 4:32 pm

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Re: Light pollution and imaging time

Postby GanymedRN » Thu Dec 06, 2018 5:19 pm

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