Hydrogen atom is an excellent case that allows understanding of the classical limit of
quantum mechanics since classical trajectories and quantum wavefunctions are known. I will
present several cases illustrating the relations between wavefunctions and classical
trajectories. The first is construction of wavefunctions, analogues of coherent states, that
mimic classical trajectories. Next I will discuss matrix elements of various physical quantities
in the classical limit. Finally I will use the classical approximation of position matrix elements
to discuss a possibility of electron localization in a Rydberg atom by measurement of the
second order correlation function of emitted radiation.