A telescope is an optical instrument that uses a lens or a mirror or other optical devices to observe distant objects. The first effect of telescope is magnify distant objects that human eyes can see the angle, angular distance smaller details. The telescope second role is the light collected by the objective lens pupil diameter (maximum 8 mm) thick, come into the human eye, so that observers can see faint objects. In 1608, Hans Lippershey, an optical business in Holland, discovered that he could see the distant scene with two lenses, and he made the first telescope in human history. After nearly 400 years of development, the function of the telescope is more and more powerful, and the distance of observation is also farther and farther. In 1609, Florence Galileo Galilei invented 40 times double mirror telescope, this is the first scientific application of practical telescope.

Personal use of small hand-held telescope should not use high rate, generally 3 ~ 12 times is appropriate, ratio is too large, imaging resolution will variation, and a severe wobble, more than 12 times the telescope generally use a tripod to get fixed. (Hubble Space Telescope, HST), is the first human space telescope, with a total length of more than 13 meters, the quality of more than 11 tons, running in the outer edge of the earth's atmosphere from the ground about 600 km orbit. The angular resolution of the Harbert telescope is less than 0.1 seconds, and every day can get 3 to 5G bytes of data. Because of the operation of the outer space, the image obtained by Harbert telescope is unaffected by the disturbance of the atmosphere, and can obtain the infrared spectrum which is usually absorbed by the atmosphere. Harbert telescope data was used for the Institute of space telescope astronomers and scientists analysis and processing. The Institute is located in Mali and Lanzhou belong to American Baltimore City Johns Hopkins University.

In 1611, the German astronomer Johannes Kepler used two biconvex lens respectively as the objective and the eyepiece, the magnification has been significantly improved, people called this optical system as the Kepler telescope.

When not using telescopes, ensure the telescope stored in ventilation, drying, clean place, to prevent mildew. A telescope is a precision instrument that must be prevented weight fall, or other strenuous actions. Non professionals do not attempt to disassemble the telescope and clean the interior of the telescope. When using telescope, pay attention to moisture, waterproof. As a precision instrument, the telescope is used as a kind of precision instrument, so it can't be used in bad conditions.

Although the basic principle of the military telescope is different from the ordinary civil telescope, there are many differences between the use of the environment and the observation object. The shell of the military telescope is made of metal instead of plastic, so as to ensure that no cracking or distortion for the long term use.