Aurora photos - assistance welcome!

[parus]

Hello! Last night I went out for about the fifth time to attempt aurora photography. I'd welcome any pointers anyone has about improving my results. They were active last night but not super intense (kp 2) while I was out. I heard they got better after I went to bed, but isn't that always how it is?

All of them are at f/3.5 which is the widest aperture on the lens I had with me and 18 mm focal length.

ISO 400, 25 sec

ISO 800, 30 sec

ISO 1600, 20 sec

ISO 6400, 6 sec

ISO 6400, 10 sec

ISO 1600, 10 sec

Here are a few from my previous attempt, an even more low-key aurora night:

ISO 400, 10 sec

ISO 400, 8 sec

 

[parus]

Some more images last night. The moon was bright and we're headed into 24-hour day months now, which made things tricky.

I think the actual auroras were about the best I can do with the equipment I've got with the display and light conditions that were on last night, but I'd really appreciate any suggestions or feedback about the compositions and whatnot...