OSLO, an acronym for Optics Software for Layout and Optimization, is a thoroughly developed program that evaluates the performance of optical systems such as astronomical telescopes and associated instrumentation. The educational version you will use is restricted to 10 refracting or reflecting surfaces, but is otherwise complete. The surfaces can be flat, spherical, or more complex curves such as parabolic, hyperbolic, and elliptical surfaces of revolution. You will use OSLO to examine the performance of a classical parabolic mirror reflecting telescope, the Hubble Space Telescope.