Page 1 AS 2001 Galactic Astronomy Galactic coordinates • α : Right ascension l : Galactic longitude • δ : Declenation b : Galactic latitude • How do we transfer between coordinate systems? NCP NGP Equatorial Galactic celestial equator α δ Galactic equator b l GC Motivated by Earth’s rotation Motivated by Galactic rotation AS 2001 Galactic Astronomy Galactic latitude, l AS 2001 Galactic Astronomy Galactic Longitude l=0=Gal. centre Galactic Latitude b=0=in plane b & l AS 2001 Galactic Astronomy