[brians]

What happens from birds, soot, bugs, airplanes, frisbees, and clouds?

[xkjkls]

They don't emit giant amounts of EMR.

[xkjkls]

Also, almost all of those serious observatory telescopes don't have to worry about. Which is what we are talking about.

[gibolt]

I'd love to read an article on how Frisbees are the biggest threat to observing the universe :D