The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
권호 표지

Design of Linear Astigmatism Free Three Mirror System (LAF-TMS) for Sky Monitoring Programs

  • Park, Woojin (School of Space Research, Kyung Hee University) ;
  • Pak, Soojong (School of Space Research, Kyung Hee University) ;
  • Chang, Seunghyuk (Center for Integrated Smart Sensors, Korea Advanced Institute of Science and Technology (KAIST)) ;
  • Kim, Sanghyuk (Optical Astronomical Technology Group, Korea Astronomy and Space Science) ;
  • Kim, Dae Wook (College of Optical Sciences, University of Arizona) ;
  • Lee, Hanshin (McDonald Observatory, Univ. of Texas at Austin) ;
  • Lee, Kwangjo (Department of Applied Physics, Kyung Hee University)
  • Published : 2017.10.10
Download PDF
⟨ Previous Next ⟩

Abstract

We report a novel design of the "linear astigmatism-free" three mirror system (LAF-TMS). In general, the linear astigmatism is one of the most dominant aberration degrading image qualities in common off-axis systems. The proposed LAF-TMS is based on a confocal off-axis three mirror system, where higher order aberrations are minimized via our numerical optimization. The system comprises three pieces of aluminum-alloy freeform mirrors that are feasible to be fabricated with current single-point diamond turning (SPDT) machining technology. The surface figures, dimensions, and positions of mirrors are carefully optimized for a LAF performance. For higher precision-positioning mechanism, we also included alignment parts: shims (for tilting) and L-brackets (for decentering). Any possible mechanical deformation due to assembly process as well as 1-G gravity, and its influence on optical performances of the system are investigated via the finite element (FE) analysis. The LAF-TMS has low f-number and a wide field of view, which is promising for sky monitoring programs such as supernova surveys.

Keywords