Jun-Ho Lee

Bio: Jun-Ho Lee is an academic researcher. The author has contributed to research in topics: Adaptive optics & Wavefront. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

A deformable secondary demonstrator for adaptive optics

Abstract: Atmospheric turbulence distorts the wavefront of the incoming light from an astronomical object and so limits the ability of a telescope to form perfect images. Adaptive optics is a combination of technologies that enable the correction of the wavefront distortion in real time. Conventional adaptive optics operate like auxiliary instruments and use additional relay optics which reduce total throughput and introduce extra IR emissivity and polarisation. Adaptive secondary mirrors avoid additional optical surfaces by providing the optical correction at an existing telescope surface (the secondary mirror). Previous studies have demonstrated the optical efficacy and mechanical feasibility of performing the adaptive correction in this way. A demonstrator is being developed to explore features and techniques applicable to a large adaptive secondary mirror and to explore manufacturing, assembly/disassembly, calibration and measurement techniques. This thesis describes the design, simulation, construction, and laboratory evaluation of the demonstrator. The thesis concludes with assessment of the viability of the approach of large adaptive secondaries for 8-m class telescopes.

Development of a carbon fiber composite active mirror: design and testing

Abstract: Carbon fiber composite technology for lightweight mirrors is gaining increasing interest in the space- and ground-based astronomical communities for its low weight, ease of manufacturing, excellent thermal qualities, and robustness. We present here first results of a project to design and produce a 27-cm diameter deformable carbon fiber composite mirror. The aim was to produce high surface form accuracy as well as low surface roughness. As part of this program, a passive mirror was developed to investigate stability and coating issues. Results from the manufacturing and polishing process are reported here. We also present results of a mechanical and thermal finite element analysis, as well as early experimental findings on the deformable mirror. Possible applications and future work are discussed.

Development of a carbon fibre composite active mirror: Design and testing

Abstract: Carbon fibre composite technology for lightweight mirrors is gaining increasing interest in the space- and ground-based astronomical communities for its low weight, ease of manufacturing, excellent thermal qualities and robustness. We present here first results of a project to design and produce a 27 cm diameter deformable carbon fibre composite mirror. The aim was to produce a high surface form accuracy as well as low surface roughness. As part of this programme, a passive mirror was developed to investigate stability and coating issues. Results from the manufacturing and polishing process are reported here. We also present results of a mechanical and thermal finite element analysis, as well as early experimental findings of the deformable mirror. Possible applications and future work are discussed.