We want to determine the emission properties of very small grains in the
fainter regions of reflection nebulae CED201 by measuring the surface
brightness distribution with ISOPHOT at different positions w.r.t.
the central star. The ISOPHOT filters at 11.3, 7.7, and also at 12.8 will be
used to probe the different PAH emission components with respect to the
continuum in the 7.3, 11.5, 20, 25, 60 and 100 micron bands. We expect to
detect variations in the spectral energy distributions due to changes in the
(i) ionization degree of PAHs (ii) hydrogenation degree of PAHs and (iii)
excitation of the different populations of small grains in the 5-100 micron
range. We request a 160 micron raster maps to consolidate
the emission contribution of the 'large' grain component.

In addition we request spectrophotometric observation with PHT-S
in the brighter inner region of CED201 and a full LWS01 spectrum
on the star to determine the continuous spectral distribution.