Observed SED of CEN 34 generated from the photometric data listed in Table 2 (diamonds), together with the best-fitting model SED (dashed line) based on a star+envelope system of M_env = 9 × 10^-5M_⊙. After dereddening (A_v = 11 mag), the extinction free model SED (solid line) can be compared to the dereddened fluxes of the reference post-AGB star IRAS 23304+6147 (triangles; Fujii et al. 2002). In addition, the best-fitting stellar blackbody (T_eff = 5260 K) is shown as a dotted line.