Aspects of the optics of the energy‐dispersive scheme for X‐ray absorption spectroscopy are discussed. The idea of a set of monochromatic focus points related to a set of local Rowland circles is introduced to account for the source‐size effect on the energy resolution. It is shown that there exists an optimized location of the position‐sensitive detector where the energy resolution is no longer source‐size dependent. In addition, the stability of the dispersive optical system has been estimated and a 10 meV energy‐scale reliability is curre