We construct the systems of generalised coherent states for the discrete and
continuous spectra of the hydrogen atom. These systems are expressed in
elementary functions and are invariant under the SO(3,2) (discrete spectrum)
and SO(4,1) (continuous spectrum) subgroups of the dynamical symmetry group
SO(4,2) of the hydrogen atom. Both systems of coherent states are particular
cases of the kernel of integral operator which interwines irreducible
representations of the SO(4,2) group.Comment: 15 pages, LATEX, minor sign corrections, to appear in J.Phys.