EXPLORATION OF WIDE-FIELD OPTICAL SYSTEM TECHNOLOGIES FOR SKY SURVEY AND SPACE SURVEILLANCE

During the past twenty-five 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 fastmoving earth-orbiting space debris. While telescope fields of view have gradually increased, a single technical approach has not emerged as the dominant design. Useful designs range from single mirrors with refractive prime focus correctors, to complex and more expensive three-mirror systems. When implemented as an operational system, each of these designs has strengths and weaknesses, and no single approach appears ideal for all situations, but some approaches tend to be more generally applicable than others. To design an effective widefield telescope for sky survey or space surveillance, it is necessary to systematically examine all components of the problem and potential solutions. Simply designing an optical system with high image quality or wide field of view is not sufficient. 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 examine the characteristics of complete system solutions for detecting deep-space objects, NEOs, and earth-orbiting space debris; and we compare these characteristics with the recently fielded Space Surveillance Telescope.