Count Steer wrote: ↑Thu Dec 07, 2023 7:28 am
I got it from here...
https://commons.wikimedia.org/wiki/File ... _night.jpg
It explains that it's a composite. (I just googled something like 'USA at night satellite').
There's so much light pollution nowadays in a lot of the world that for astronomers this sort of map is essential:
https://www.lightpollutionmap.info/
There are a couple of others https://darksitefinder.com/maps/world.html, https://www.darkskydiscovery.org.uk/dar ... s/map.html but they all do the same thing of giving you the Bortle Scale measure of your local sky. There's no substitute for a really dark sky for astronomy.