The midnight sun

I've just realised, with considerable consternation, that since Raoul and his crew are spending considerable amounts of time north of the Arctic Circle they are going to be running into the 'midnight sun' issue, which means that all the night-time scenes are wrong :-(

I'm not sure quite what I'd decided upon for which bits of the journey, but since the "Requin" sets sail at the end of March he probably meets up again with Christine around late May, at which date Tromsø is under perpetual sun, and so will the areas further north be :-( At Spitzbergen the sun is constantly in the sky from late April. https://en.wikipedia.org/wiki/Midnight_sun

I made reference to "the long eerie twilight of approaching summer in the North", but it never for a moment occurred to me that they were so far north that it simply wouldn't get dark at all...