Wide-field and large aperture optical system design for ground-based photoelectric detection

Abstract

Detection and recognition of space objects with ground-based photoelectric systems is one of the major technical ways for space situational awareness. During the past thirty years, there has been significant development of optical telescopes dedicated to wide-field surveys of time-dependent deep space phenomena, slow-moving near-earth objects (NEOs) and fast-moving earth-orbiting space debris. While telescope fields of view have gradually increased, a single technical approach has not emerged as the dominant design. To design an effective wide-field telescope for sky survey or space surveillance, It is necessary to carefully match the characteristics of the optical system (layout, aperture, focal ratio and modulation transfer function) with those of the observing site (sky brightness, transparency, seeing and elevation), the detector (pixel pitch, quantum efficiency, read rate and read noise), and the observing program (target brightness, target motion, observing strategy and feature extraction software). In this paper, we design a telescope with wide field of view (≥2.5°×3.5°) and large aperture (1.1m). The focal length of the system is 1.5m, F/# is 1.36. Because of the small Fnumber and wide field of view, we choose the prime focus corrector structure which has single mirrors with refractive prime focus correctors. Moreover, the especial requirements of the Modulation Transfer Function (MTF), spot, energy concentration, and distortion etc. are all satisfied.