Design of compact continuous high zoom-ratio gun sighting telescope optical system

In order to meet the needs of individual soldier platforms, a 1^\times \sim8^\times compact continuous high zoom-ratio gun sighting telescope was designed. The design method and thinking of the gun sighting telescope was expounded. Firstly, the index decomposition and Gaussian optical calculation of objective lens, relay system and eyepiece were carried out according to the design index, so as to preliminarily evaluate the envelope size and complexity of the whole optical system. Then, according to the Gaussian optical calculation results, the optical design and evaluation of each component of the lens were carried out separately. Particularly, three problems were solved, such as the power ratio selection of relay system in the design of continuous high zoom-ratio gun sighting telescope, the matching of pupil between equivalent objective lens and eyepiece, and the evaluation of image quality at the middle image plane differentiation plate. The design results show that the objective lens diameter is ϕ24 mm, the eyepiece diameter is ϕ36 mm, the total optical length is 228 mm, and the line of sight error caused by the eccentricity error (0.01 mm) at the high magnification end is about 20″. The system has a compact structure and good imaging quality, which meets the requirements for the use of visual optical instruments.