Improved reflective/diffractive hybrid wide field Cassegrain telescope

Abstract

An improved reflective / diffractive hybrid wide field Cassegrain telescope is characterized in that a secondary lens is arranged on the left side of a prime lens; a light screen is connected to the back of the secondary lens; a follow-up corrective lens assembly is arranged on the right side of the prime lens; the follow-up corrective lens assembly consists of three sequential lenses that are all made of ordinary materials; the prime lens and the secondary lens are aspheric lenses and merely conicoid lenses, and diffractive optical elements are etched on the lenses, so as to facilitate correcting the systematic aberration. The invention has the characteristics that: firstly, the prime lens and the secondary lens are additionally provided with the diffractive optical elements on the basis of the conicoid, so as to meet the requirements of systematic wide field and improve the imaging quality; secondly, satisfactory imaging effect can be achieved by adopting the special materials or the complicated surface shapes in the design; and thirdly, as the diffractive optical elements in the system are much easier to machine and manufacture, no further requirement on the manufacturing technology is added.

Description

technical field [0001] The invention relates to a Cassegrain telescope, in particular to an improved inverse / diffraction hybrid large-field Cassegrain telescope. Background technique [0002] The Cassegrain telescope is a typical type of catadioptric telescope system, which can take into account the advantages of both refracting and reflecting telescopes. The system is composed of two reflectors, the primary mirror and the secondary mirror. The incident light is firstly reflected by the primary mirror to reach the secondary mirror, and then reflected by the secondary mirror again through the central opening of the primary mirror for final imaging. Such as figure 1 As shown, the primary mirror and secondary mirror of the traditional Cassegrain telescope are composed of a large paraboloid and a small hyperboloid mirror respectively. Because the optical path through the reflective objective lens is folded inside the system, compared with the refractive objective lens, the len...

AI Technical Summary

Problems solved by technology

The general Cassegrain system mirror has no chromatic aberration, and can work in a wide band from ultraviolet to infrared. Although it has a good imaging quality for the point on the axis, the light is reflected by the mirror and produces central occlusion and Stray light and off-axis aberrations are not eliminated, especially coma; with the demand for larger apertures and larger field of view, other aberrations also appear, so the field of view of the Cassegrain system is made very small

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