ISSN: 2277-9655 [Hammod* et al., 6(8): August, 2017] Impact Factor: 4.116 IC™ Value: 3.00 CODEN: IJESS7 http: // www.ijesrt.com© International Journal of Engineering Sciences & Research Technology [178] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY DESIGN AND ANALYSISA ZOOM CASSEGRAIN TELESCOPE COVER MIDDLE IR REGION USING ZEMAX PROGRAM Haider Y. Hammod *1 , Saaid F. Hassan 2 , Intisar A. Naseef 3 *1,2&3 Ministry Of Science And Technology/Directorate Of Material Research /Center Of Laser Research DOI: 10.5281/zenodo.839159 ABSTRACT 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. KEYWORDS: Cassegrain telescope, DesignCassegrain, ZoomCassegrain, Telescope Infrared. I. INTRODUCTION Early forms of zoom lenses were used in optical telescopes to provide continuous variation of the magnification of the image, and this was first reported in the Proceedings of the Royal Society in 1834. Can using the zoom only a few kilometers, or it can extend to 100 kilometers or more. Accurately imaging a missile trajectory under these changing conditions requires either multiple imaging systems with fixed focal lengths or a zoom lens system that is capable of changing its magnification to accommodate the variation in object distance. A zoom system offers significant advantages in that it eliminates the need for multiple setups of the test equipment or the time-consuming and costly task of changing fixed imaging systems during the tests. In addition, the use of a single zoom lens system can eliminate the need for an inventory of multiple imaging systems, thereby reducing the costs and logistics of carrying multiple systems in inventory [1].Combines infrared telescope infrared (heat) of the space objects. Most telescopes infrared reflective optical telescopes, equipped with detector instead of the eyepiece.And gives any object, which is at room temperature, large amounts of infrared radiation due to the heat that keeps them. Infrared light has fairly long wavelengths that pass through clouds of dust betterthan light with shorter wavelengths. Infrared telescopes are used to observe objectssurrounded by dust, such as young stars being born inside nebulae. Because allwarm objects give off infrared light, infrared telescopes are chilled so that theywon’t detect their own glow. The lifespan of an infrared telescope is limited by howlong the telescope can be kept cool[2].We choose aCassegrain system because of higher throughput and ease of fabrication and assembly in addition to our confidence in maintaining alignment in a rugged environment, take advantage of the heat can be captured effectively, such as a mammal, cars, etc., of great benefit in the military. II. THEORY Cassegrain telescopes are optical telescopes that combine specifically shaped mirrors and lenses to form an image. This is usually done so that the telescope can have an overall greater degree of error correction than their all lens or mirror counterparts with a consequently wider aberration free field of view. Their designs can have simple all spherical surfaces and can take advantage of a folded optical path that reduces the mass of the telescope, making them easier to manufacture [3]. A mirror has substantially less spherical aberration than a lens of equivalent focallength. In addition, the spherical aberration of a concave mirror is opposite in sign tothat of a positive lens. Therefore, several researchers have proposed the use of a weak negative lens in conjunction with a concave mirror.Proposeda weak aspheric corrector at the center of curvatureof a spherical mirror.In the