Thursday "xoves" and Romanian "joi". This is also reflected in the p-Celtic Welsh "dydd Iau". The astrological and astronomical sign of the planet Jupiter (♃) is sometimes used to represent Thursday. Since the Roman god Jupiter was identified with Thunor (Norse Thor in northern Europe), most Germanic languages name the day after this god: "Torsdag" in Danish, Norwegian, and Swedish, "Hósdagur"/"Tórsdagur" in Faroese, "Donnerstag" in German or "Donderdag" in Dutch. Finnish and Northern Sami, both non-Germanic (Uralic) languages, uses the borrowing "Torstai" and "Duorastat". In the extinct Polabian Slavic language, it was "perundan", Perun being the Slavic equivalent of Thor. There
IAU (1976) System of Astronomical Constants and in 1979 and 1980 by a theory of nutation . There were no reliable rotation elements for most planets, but a joint working group on Cartographic Coordinates and Rotational Elements was installed to compile recommended values The IAU(1976) system is based on the astronomical system of units: IAU commission 4: , IAU (1976) System of Astronomical Constants The International Astronomical Union at its XVIth General Assembly in Grenoble in 1976, accepted (Resolution No. 1 a whole new consistent set of astronomical constants recommended for reduction of astronomical observations, and for computation of ephemerides. It superseded the IAU's previous recommendations