Fan Mountain 31-inch Tinsley Reflector

General System Data: Classical Cassegain system
    Effective focal ratio - f/15.484
    Effective focal length - 480.0 inches
    View Optical layout
(1) Primary Mirror: Parabolic
    Outer Diameter - 32.0 inches
    Inner Diameter - 8.6 inches
    Thickness - 8.0 inches
    Clear Aperture - 31.0 inches
    Focal Length - 120 inches
    Material - ULE
    Reflective coating - Aluminum
(2) Secondary Mirror: Hyperbolic
    Outer Diameter - 8.75 inches
    Thickness - 1.5 inches
    Clear Aperture - 8.50 inches
    Focal length - 70.81 inches
    Material - ULE
    Reflective coating - Aluminum
(3) Focal Plane: Cassegrain focus
    Field Diameter - 5.5 inches
    Angular Field Diameter - 39.4 arcmin
    Plate Scale - 16.92 arcsec/mm
A ZEMAX lens file for the 31-inch is available. It was created using ZEMAX version 8.0. This file can be saved in text format and read directly into ZEMAX for further analysis.