DESIGN AND ANALYSISA ZOOM CASSEGRAIN TELESCOPE COVER MIDDLE IR REGION USING ZEMAX PROGRAM

The goal of the project is to find an optimal design of zoom -Cassegrain telescope which is popular for amateur astronomers. Also,the objective function of the optical design is to reduce the aberrations to provide aclear image. Cassegrain telescope has been designing and analysis by using (Zemax) software. The full field of view of the objective lens angle to 0.383°, the focal length to 747,748,750 and751mm, Back focal distance BFD 41 mmand Entrance pupil diameter 218.The system consists of a fixed focal length of the objective lens, zoom eyepiece. The eyepiece continuous zoom the zoom telescope system especially Cassegrain the zoom telescope system applications a wide range of zoom optical system .Wide range of wavelength extends from (3.2--4.2μm) and diffraction limited over a large field of angles with F/#3.4 also studied. We find that less aberration that hasbeenreached in the design values are(±0.5 to ±2.2) µm.