Scientifically speaking, I think Norhtern Lights activity depends solely on solar wind. And solar wind activity is not affected by the moon (which causes the solar eclipse), nor a comet.

Anyhow, knowing that there is a scientific explanation for the lights, it is still a spectacular show. It must have been even more awesome for the ancestors.

Spotting Northern Lights is very unpredictable, so it is mostly a question of luck. And some years are more active than others - I guess there is rhythm like 4 to 6 active years and then same amount of less active years and so on. (at the moment I'm too tired to check the details, maybe wikipedia knows =) )