Equations (4) and (5) are iterative equations and the starting values of and are set to infinity. When independent variables and are determined according to the limitation of the total track of the objective, the unknown data () used to calculate and in Eqs. (4) and (5) can be acquired by real ray tracing with the commercial optical design software (since NAO, YOB, and CA were determined before, the ray tracing of G1 can be processed). By substituting the above ray-tracing data and into Eqs. (4) and (5), new values of and can be calculated. Updating the values of and and then tracing the ray path again, new ray-tracing data will be obtained. After following such iterative computations several times, the values of and will converge and the final results can be obtained. It should be noticed that the values of , and should be set appropriately to obtain an adequate configuration of G1.