A system including a first component, a second component disposed radially adjacent to the first component, and a centralizer disposed between the first component and the second component for at least partially filling a radial clearance between the first component and the second component. A method employed in this device is described. The grating or a telecentric stop between the grating and prism is placed at a focal point of the lens in a telecentric arrangement so that equal magnification is achieved at the detector array.