On Planck simulations: towards "2-nd order" analyses

We simulate Planck observations by adopting a detailed model of the microwa ve sky including monopole, dipole, anisotropies of the cosmic microwave bac kground (CMB) and galactic and extragalactic foregrounds. We estimate the i mpact of main beam optical aberrations on CMB anisotropy measurements in pr esence of extragalactic source fluctuations and we discuss the main implica tions for the Planck telescope design. By analysing the dipole pattern, we quantify the Planck performance in the determination of CMB spectral distor tion parameters in presence of foreground contaminations.