% Double Gauss Lens parameters:
lambda   550[nm]                                                         Nominal vacuum wavelength

theta_x  0[deg]                                                          Nominal x field angle
theta_y  0[deg]                                                          Nominal y field angle

N_ring   18                                                              Number of hexapolar rings
P_nom    58.941[mm]                                                      Nominal entrance pupil diameter

vx       tan(theta_x)                                                    Ray direction vector, x-component
vy       tan(theta_y)                                                    Ray direction vector, y-component
vz       1                                                               Ray direction vector, z-component

z_stop   Tc_1+T_1+Tc_2+T_2+Tc_3+T_3                                      Stop z-coordinate
z_image  Tc_1+T_1+Tc_2+T_2+Tc_3+T_3+Tc_4+T_4+Tc_5+T_5+Tc_6+T_6+Tc_7+T_7  Image plane z-coordinate

P_fac1  -1.15                                                            Pupil shift constant 1
P_fac2  -0.60                                                            Pupil shift constant 2
P_fac    P_fac1+P_fac2*sin(sqrt(theta_x^2+theta_y^2))                    Pupil shift factor
dx       (dz+P_fac*z_stop)*tan(theta_x)                                  Pupil center, x-coordinate
dy       (dz+P_fac*z_stop)*tan(theta_y)                                  Pupil center, y-coordinate
dz      -1[mm]                                                           Pupil center, z-component