We report K'-band imaging observations of the reflection nebula associated
with Cepheus A East covering the time interval from 1990 to 2004. Over this
time the reflection nebula shows variations of flux distribution, which we
interpret as the effect of inhomogeneous and varying extinction in the light
path from the illuminating source HW2 to the reflection nebula. The obscuring
material is located within typical distances of approximately 10 AU from the
illuminating source.Comment: 22 pages, including 6 figures, accepted for publication in The
Astronomical Journa