Design Optimization Model for a Schmidt-Cassegrain Telescope ME ...

Figure 3.2: Optical Layout of Newtonian Telescopeto the Newtonian, the central obstruction causes a large loss of contrast and imagesharpness. However, reducing the size of the secondary mirror can cause an increasein aberrations. Thus, the designer must review the tradeoffs of loss of light and thepresence of aberrations in a Cassegrain system. Unwanted light can easily make itsway into the focal area of a Cassegrain system, thus baffles must be introduced toblock stray light. However, this further increases the loss of light entering the eyepiece.Figure 3.3: Optical Layout of Cassegrain TelescopeThe Schmidt corrector is an aspheric refraction lens inserted to help reduce monochromaticaberrations with spherical mirrors. The profile of a Schmidt corrector dictateshow the rays are refracted through the profile. However, since the corrector is arefracting element, it creates chromatic aberrations which can be measured throughspot diagrams. The corrector lens is usually an addition to a telescope with a reflectivesurface.The telescope type that will be modeled in this paper is a Schmidt-Cassegraintelescope(SCT). This is a very popular telescope among astronomers due to its compactness,transportability and excellent reduction of chromatic aberrations. The SCTcombines the Cassegrain telescope with a Schmidt corrector for a total of three op-8