Design of a built-in baffle for a Ritchey-Chretien optical system

A baffle effectively prevents direct rays of stray light from entering an optical system. Existing design methods can result in very long outer baffle lengths, increasing the weight and volume of the optical system, or large secondary mirror baffle sizes, increasing the central obscuration and resulting in the reduction of the illumination beam on the image. To overcome these challenges, a design method for a built-in baffle is presented. The designed built-in baffle for a typical Ritchey-Chretien optical system is compared with a conventionally designed baffle. The results show that when the length of outer baffle is shortened from 3456 to 2349.9 mm, the modulation transfer function (MTF) increases from 0.361 to 0.421 in case 1, and when the length is shortened from 3456 to 1924.2 mm, the MTF increases from 0.361 to 0.408 in case 2. Meanwhile, the stray light suppression capability is close to that of the traditional method.