Optical relay system

An imaging device comprising an optical relay system, wherein the optical relay system comprises two halves disposed symmetrically about an aperture stop, wherein each one of the two halves comprises a plurality of rotationally symmetric optical elements forming an objective and a compound prism comprised of a plurality of dispersing prisms, and wherein the compound prisms are located between the objectives and the aperture stop,

• wherein at least one of the following conditions is met:
• the plurality of prisms forming the compound prisms have a small difference in refractive index at the center wavelength, in particular the difference in refractive index at the center wavelength is <0.001, and
• the plurality of prisms has a larger difference in refractive index at the end points of the spectral range, and
• wherein two measures of refractive index dispersion are defined as follows:
• v700=(n700−1)/(n400−n700),
• P700=(n400−n700)/(n400−n1000)
• where n400, n700, and n1000 are the refractive indices at 400 nm, 700 nm, and 1000 nm, and wherein the objective is comprised of five rotationally symmetric lens elements (L1, L2, L3, L4, L5), wherein a first lens element and a second lens element (L1, L2) form a first doublet (D1), a third lens element and a fourth lens element (L3, L4) form a second doublet (D2), and a fifth lens element is a positive singlet, wherein the objective satisfies the following expressions:
• −1.73<ΦD1/Φobjective<−1.57
• 0.92<ΦD2/Φobjective<1.01
• 0.89<ΦL5/Φobjective<0.98
• n700 for L1>1.85
• |ΔP700/Δv700|<0.007 for D1
• |ΔP700/Δv700|<0.0001 for D2
• v700 for L5>24,
• where Φobjective is the optical power of the objective, ΦD1 is the optical power of the first doublet (D1), ΦD2 is the optical power of the second doublet (D2), ΦL5 is the optical power of the singlet (L5), and ΔP700/Δv700 for a doublet is the difference in P700 divided by the difference in v700 for the two glasses comprising the doublet.