Thank you, Andrew, Peter, Akira and Ølvind.
Akira - all I can say is, no "trickery" was involved, nor any particularly difficult or lengthy processing. The camera was on a tripod, of course. There was a very bright and almost full moon, strongly coloured by the atmosphere that evening which made exposure rather easy. Stars are very small but actually very bright, and the exposure - dictated by the large are pf bright snow, was short enough to keep the sky dark - this makes the stars more visible, of course. So I didn't have to do much, exposure-wise. Processing - I selected the whole area of sky and played with contrast a little; then I selected the snowy area and did something similar with that. A little noise suppression and gentle sharpening and it was finished.
Ølvind - you are right - something wrong with that one.