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Radiance.....what is it and how do I compare it to other sites?
Looking at a reputable light pollution map and clicking on my backyard I get a Radiance figure of 0.17.....what do I compare this to?
How do I put this number in perspective?
Just by walking outside I know that it is good.......it's very dark and I can't discern any pollution.
What level of "radiance" are the rest of you taking photos in?
billdan
05-09-2017, 11:41 PM
I haven't heard of that terminology before (radiance) when it comes to light pollution.
You can purchase a Sky Quality Meter (SQM), which will measure the quality of the sky above you, generally in the suburbs you get a reading of 18 and over 21 at a dark site.
In the USA they describe the sky quality as colored zones, with a red zone being inner city, orange/yellow for suburbs and green/blue for out in the country.
Where I live (last time I checked), my side of the street is a yellow zone, but the guy across the road is in a green zone.
Cheers
Bill
Sounds like you may need to make an offer on the house across the road!
Thanks for th eon for anyway....I've done some mor eresearch and puns radiance is a logarithmic scale and basically useless as any form of measure.
......but I've come across another measure which works really well......walk outside and open my eyes......if I can see a good number of stars with the naked eye then the going is good hahahaha.
Couple of links to get you started:
https://www.globeatnight.org/
http://cires.colorado.edu/Artificial-light
Star counting is not as silly as it sounds
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