The constraints of building a remote sensing satellite, with limited volume, weight and to acquire high image quality have resulted in innovative approaches to the design of the telescope as an essential and effective part of electro-optical (E-O) remote sensor performance parameters. The majority of the Earth observation satellites payloads are based on reflective
telescopes due to their compact size, reduced weight of mirrors over lenses for the same entrance aperture diameter, in addition that reflective telescopes are free of chromatic aberrations. In this paper, the Cassegrain configuration layouts, as reflecting telescopes, and their preliminary design evaluation are presented. A comparison among these reflecting
telescope layouts is executed using ZEMAX software package. Finally, a simulation of an optical telescope based on a proposed case study is developed using ZEMAX.