refractor telescopes manufacturers

 In a broad sense, telescopes include not only optical telescopes operating in the visible light band, but also radio, infrared, ultraviolet, X-ray, and even gamma-ray telescopes. We are limited to optical telescopes. In 1609, Galileo produced the first telescope. It has a history of nearly four hundred years. During this period, it has experienced a major leap. According to the type of objective lens, it can be divided into three types: 1. Refracting telescope The objective lens of a refracting telescope is composed of a lens or lens group. The early objective lens was a monolithic structure, with serious chromatic aberration and spherical aberration, which made the celestial bodies viewed with colored spots. In order to reduce chromatic aberration, people desperately increased the focal length of the objective lens. In 1673, J. Hevelius built a 46-meter-long telescope. The entire lens barrel was hoisted on a 30-meter-high mast, requiring multiple people to pull it with a rope. Moving