A projection apparatus for generating a moving star field and a cloud-like
effect comprises a means for generating a cloud-like effect using at
least one non-coherent light source, a means for generating a moving star
field using at least one coherent light source and a means for regulating
and supplying electric power. The means for generating cloud-like effect
using at least one non-coherent light source comprises at least one pair
of condenser lenses and an interferential filter wheel rotated by a
motor, disposed between at least one pair of condenser lenses. The means
for generating the moving star field using a coherent light source
comprises a grating wheel rotated by a motor and a diffractive optical
element disposed between the at least one coherent light source and the
grating wheel.