Wow. I have never seen any like that photo with the streaky green and purple curtains. I've seen all of the others as well as some that are not listed there.

There are so many kinds, all dependent on the height and the ions, I think it is. Once I saw white 'smoke rings' form until the whole sky was covered with linked rings. This was in May of 1993.

In Juneau I've seen them in every month but June or July. The sky is just too light in those months. In Juneau, of course, our skies are very often too cloudy to have much hope of seeing them. That is why they are more reliably seen in the dry, clear Interior of Alaska than in the Southeast rain forest. And of course, a full moon frequently makes the sky too light no matter what month it is.

At night I watch the Northern Lights
Stream across the sky
Silver and gold in ripples and folds
Of a purple scarf flung high.
Green canopy of the Northern Lights!
Gleaming stars hang nigh
All nourish my soul in the crystal cold
Alone in the Northern Lights
Alone in the Northern Lights