Corrector Glass                ne
Corrector Diameter          [mm]
Corrector Location           [mm]
Mirror Focal Length         [mm]
+ Lens Edge Tickness       [mm]
- Lens Center Tickness     [mm]
Back Working Distance    [mm]
Half Field Angle               [deg.]  

*** This Calculator is based on Harrie Rutten and Martin van
    Venrooij book "Telescope Optics: Evaluation and Design"