Reflective telescope.

This project presents the optical design of a Ritchey–Chrétien (RC) reflecting telescope with an effective focal length of 5000 mm and an F/6 focal ratio. The system employs a two-mirror reflective configuration, complemented by refractive corrector elements to address residual optical aberrations and support image quality across the specified field of view.

The optical prescription was developed and evaluated in Zemax OpticStudio, with the system configured for a maximum radial field angle of 0.47°. The design combines the aberration-correcting characteristics of the RC mirror configuration with additional refractive correction, demonstrating an approach to developing long-focal-length telescope optics.

Two-Mirror Reflective Architecture

The telescope employs a primary and secondary mirror with aspheric profiles characteristic of the Ritchey–Chrétien configuration. This architecture is intended to control off-axis aberrations, particularly coma, while providing a long effective focal length within a compact folded optical arrangement.

Refractive Aberration Correction

Two refractive elements are incorporated into the optical train to provide additional aberration correction. Their optical parameters and positions form part of the overall system prescription, complementing the reflective optics in achieving the intended imaging performance.

Long-Focal-Length Optical Design

With a 5000 mm effective focal length and an F/6 focal ratio, the system is configured for long-focal-length astronomical imaging applications. The specified field extends to a radial angle of 0.47°, making off-axis image quality an important consideration in evaluating the design.

Optical Design and Evaluation

The complete prescription was developed in Zemax OpticStudio, providing a framework for evaluating the optical configuration, ray propagation, and image formation across the specified field. Further performance characterization can be presented through spot diagrams, MTF plots, wavefront analysis, and field-dependent aberration results.

Conclusion

This project demonstrates the optical design of a long-focal-length reflecting telescope combining an RC mirror configuration with additional refractive correction. The 5 m effective focal length, F/6 focal ratio, and defined field coverage establish the key parameters of the system.

At Devion Optics, we explore optical architectures for demanding imaging applications, combining reflective and refractive optical design techniques to develop tailored optical solutions.