  Coherent states provide an appealing method to reconstruct efficiently a pure
state of a quantum mechanical spin s. A Stern-Gerlach apparatus is used to
measure (4s+1) expectations of projection operators on appropriate coherent
states in the unknown state. These measurements are compatible with a finite
number of states which can be distinguished, in the generic case, by measuring
one more probability. In addition, the present technique shows that the zeroes
of a Husimi distribution do have an operational meaning: they can be identified
directly by measurements with a Stern-Gerlach apparatus. This result comes down
to saying that it is possible to resolve experimentally structures in quantum
phase-space which are smaller than hbar.
