  Ground and in flight calibrations of the MECS experiment on board Beppo-SAX
have demonstrated that this is currently the best X-ray imaging experiment
above 3 keV. The MECS on-axis PSF has a half power radius of about 1 arcmin.
Moreover due to a fortunate combination of detector and mirror PSFs the total
PSF depends only weakly on the energy. Finally the degradation of the PSF with
off axis angle is negligible within an off-axis angle of 10 arcminutes.
Encouraged by these results we developed techniques to analyze galaxy clusters
observed with Beppo-SAX. In this proceeding we quantify spectral distortions
introduced by the energy dependent PSF when performing spatially resolved
spectroscopy of the core of the Virgo cluster.
