(a) Spot diagrams for the VT-137q design in the integral waveband 0.40–0.82 μm; the box width is 52.4 μm (1.″0). (b) Polychromatic encircled energy diagram in the integral waveband for VT-137q. The curves correspond successively to the diffraction limit, the axial beam, and the field angles of 0.°5, 0.°75, 1.°0, 1.°1, and 1.°25.