This webpage provides a brief description of two types of telescopes: dobsonian and cassegrain. Dobsonian telescopes are simple, low-cost and easy to use. They have a large aperture and a short focal length, which makes them ideal for observing deep-sky objects. Cassegrain telescopes are compact, versatile and sophisticated. They have a long focal length and a small aperture, which makes them suitable for observing planets and other bright objects. The webpage compares and contrasts the features, advantages and disadvantages of these two telescope