% Prescription from Allen Report.
% See also OTA Handbook, v1.0, May 1989; Chris Burrows, STSCI.

% Global parameters:
nix         0.0           Global optical axis, x-component
niy         0.0           Global optical axis, y-component
niz         -1.0          Global optical axis, z-component
lam_vac     550[nm]       Vacuum wavelength
theta_x1    0[arcmin]     Field angle 1, x-component
theta_y1    0[arcmin]     Field angle 1, y-component
theta_x2    5[arcmin]     Field angle 2, x-component
theta_y2    0[arcmin]     Field angle 2, y-component
theta_x3    10[arcmin]    Field angle 3, x-component
theta_y3    0[arcmin]     Field angle 3, y-component
N_ring      10            Number of hexapolar rings
P_nom       2400.0[mm]    Nominal entrance pupil diameter
F_nom       24.0          Nominal focal ratio
f_nom       F_nom*P_nom   Nominal focal length

% Primary mirror parameters:
R_prim      -11040.0[mm]  Primary mirror radius of curvature
k_prim      -1.0022985    Primary mirror conic constant
f_prim      R_prim/2      Primary mirror focal length
d0_prim     2450.0[mm]    Primary mirror full diameter
d1_prim     0             Primary mirror surface diameter
dc_prim     0             Primary mirror clear diameter
dh_prim     600.0[mm]     Primary mirror central hole diameter
Tc_prim     125.0[mm]     Primary mirror center thickness
Z_prim      0[mm]         Primary mirror z position (absolute)
np_extra    10            Primary mirror number of azimuthal extra points

% Secondary mirror parameters:
R_sec       1358.000[mm]   Secondary mirror radius of curvature
k_sec       -1.49600       Secondary mirror conic constant
d_sec       395.0[mm]      Secondary mirror diameter
Tc_sec      75.0[mm]       Secondary mirror center thickness
Z_sec       -4906.071[mm]  Secondary mirror z position (relative to primary vertex)

% Nominal image surface position:
Z_bfl       1500.000[mm]   Image surface back focal length (relative to primary vertex)
Z_image     Z_sec-Z_bfl    Image surface z position (relative to secondary vertex)
hw_image    200.0[mm]      Image surface half width   

% Exit pupil position:
Z_exit      -7003.51[mm]   Exit pupil z position (relative to image surface)

% Obstruction:
Z_obs       100.0[mm]       Obstruction offset (from secondary vertex)
eta_obs     0.33            Obstruction fraction
d0_obs      eta_obs*P_nom   Obstruction diameter

% Derived parameters:
m           abs(f_nom/f_prim)     Transverse magnification of secondary
beta        abs(Z_bfl/f_prim)     Ratio of back focal length to primary focal length
Cp          2*(1/R_sec-1/R_prim)  Petzval curvature

% Mesh parameters
max_prim    50.0[mm]                Maximum element size, primary
max_sec     max_prim*d_sec/dc_prim  Maximum element size, secondary

% Ray launch parameters
vz   1                 Ray direction vector, z-component
vx1  tan(theta_x1)     Ray direction vector, x-component
vy1  tan(theta_y1)     Ray direction vector, y-component
vx2  tan(theta_x2)     Ray direction vector, x-component
vy2  tan(theta_y2)     Ray direction vector, y-component
vx3  tan(theta_x3)     Ray direction vector, x-component
vy3  tan(theta_y3)     Ray direction vector, y-component
dz   2*Z_obs-Z_sec     Ray launch z-coordinate
dx1  dz*tan(theta_x1)  Ray launch, field 1, x-coordinate
dy1  dz*tan(theta_y1)  Ray launch, field 1, y-coordinate
dx2  dz*tan(theta_x2)  Ray launch, field 2, x-coordinate
dy2  dz*tan(theta_y2)  Ray launch, field 2, y-coordinate
dx3  dz*tan(theta_x3)  Ray launch, field 3, x-coordinate
dy3  dz*tan(theta_y3)  Ray launch, field 3, y-coordinate

% Airy disc definition:                                   
theta_Airy  1.22*lam_vac/P_nom  Airy disc angular radius
r_Airy      f_nom*theta_Airy    Airy disc radius