I just wondered whence did so strange a spelling came from. After all, most of us would be accustomed to write the name rather as Náttsól, i.e. with two acute accents. For anybody yet curious, Wikipedia comes with an explanation of this obvious mistake: "In Norwegian (both Bokmål and Nynorsk), the grave accent is used to separate words which would otherwise be identical, for instance og (and) and òg (too). Popular usage, possibly because Norwegian rarely uses diacritics, often leads to a grave accent being used in place of an acute accent." (cf. Grave accent, 1.4 Disambiguation).