The current Galactic Coordinate System was adopted by the International Astronomical Union in 1958. The centre of the System was defined to be Sagittarius A, a complex radio source at the centre of the Milky Way, at RA = 266°.448 and Dec = -28°.969. However, recent studies show that the dynamical centre of the Galaxy is Sagittarius A*, a compact radio source and a component of Sagittarius A which is positioned at RA = 266°.417 and Dec = -29°.008. A 0°.07 shift in the centre implies that the current Galactic Coordinate System is not updated. By analysing the latest catalogues of galactic tracers such as HII regions, Open and Embedded Clusters, etc., we calculated the position of the North Galactic Pole and revised the old Coordinate System. The revised parameters describing the Coordinate System are: RApole = 192°.783 ± 0°.015, Decpole = 27°.153 ± 0°.007 and θ position angle = 122°.953 ± 0°.007. This project was supported in part by NSF award PHY-1156339.
Publication:M. Karim and E. Mamajek, Revised Geometric Estimates of the North Galactic Pole and the Suns Height Above the Galactic Midplane , MNRAS, first published online in October 2016