Saturn threw a comet out of the solar system at 6,700 mph. Here's how

[billslugg]

I was in Peru looking at Halley from 10,000' elevation and the airglow was so bright you could read the paper. It was brighter than Halley's tail was outside 1/2° from the nucleus. I don't know why it was so bright.

 

[Helio]

I was in Peru looking at Halley from 10,000' elevation and the airglow was so bright you could read the paper. It was brighter than Halley's tail was outside 1/2° from the nucleus. I don't know why it was so bright.

I too was surprised when learning they close mountain observatory domes when particle counts are too high. High counts also brighten the sky, of course.

 

[billslugg]

I may have been in the South Atlantic Anomaly. Centered over Argentina, extends over all of South America plus bottom fourth of Africa. Earth magnetic field is about one third of normal. Lots of particles can get in. Normal skyglow is faint, due to longer term relaxation of excited molecules that got that way during the daytime. This skyglow was almost like a pure white aurora. Faint, but enough to swamp a comet's tail.

 

[Helio]

I may have been in the South Atlantic Anomaly. Centered over Argentina, extends over all of South America plus bottom fourth of Africa. Earth magnetic field is about one third of normal. Lots of particles can get in. Normal skyglow is faint, due to longer term relaxation of excited molecules that got that way during the daytime. This skyglow was almost like a pure white aurora. Faint, but enough to swamp a comet's tail.

That's interesting. Is this ever an issue for the monster scopes in Chilie?

 

[billslugg]

I suppose sky brightness would affect certain type of observations. I see it must be entered into the calculator when determining telescope limiting magnitude.