We returned yesterday from a similar trip (Hurtigruten - MS Vesteralen), the tripod is a must, as many people on the boat didn't bother with one (only noticed 4 tripods on the whole trip and two of those were mine and my partners) as the other people thought the movement of the boat would make it pointless, but we got the photos and they didn't.
As someone else mentioned your daughter will need her 10-24 lens for the lights due to the huge amount of sky they can take up, but she should also consider taking her longer lens as I used my 100-400 a fair bit as well as there could be the chance of seeing a Sea Eagle.
In terms of the comment about the lights being on the wane now, I think it is from about October to March when you are most likely to see them. We were lucky enough to see them on three nights (they do announce sightings on the ship), but the first night to the naked eye it simply looked like light coloured grey cloud, yet when I just took a photo the green could then be seen, so she will need to look closely.
Although on the other two nights they looked more like you would expect them to see, based on what you see in photos and on TV. She also needs to make the effort to see them as I would say at least half of the people on our boat didn't make an effort and therefore didn't see them!
On another mater she may wish to take some sea sickness pills as for us at least it was a little rough at times due to the fact you are sometimes in open water, but the Vesteralen is one of their older ships so another one might be different and it was also rather windy.
Tell her to watch out for the ice and cold water from Neptune as part of the ceremony for crossing the Arctic Circle!
please explain?
