The main objective of this book is designing Next Generation Optical Telescope (NGOT) to gather information from a far region of space and illustrates with simulation the Adaptive Optics system. The Quality of images and spectra taken at ground-based astronomical observations is degraded by distortions in the Earth's atmosphere. Compensation of the atmospheric seeing can be achieved using the technology of Adaptive Optics, a technique which is being pursued by every major ground-based observatory. The techniques of adaptive Optics are those by which telescope optics is adjusted on a rapid time scale to compensate for distortions in the wave front entering a telescope.