AN SO(2) GAUGE DESCRIPTION OF THE KEPLER-PROBLEM

Starting from the fact that not all the unitary irreducible representations of the symmetry algebra which accounts for the ''accidental'' degeneracy of the hydrogen energy levels do occur as energy eigenspaces, an SO(2) gauge description of the Kepler problem is given. This extended system is used to test an algebraic procedure for the quantization and reduction of gauge systems, which is entirely based upon observable quantities.