Development of Linear Astigmatism Free—Three Mirror System (LAF-TMS)

Park, Woojin; Chang, Seunghyuk; Lim, Jae Hyuk; Lee, Sunwoo; Ahn, Hyo Won; Kim, Yunjong; Kim, Sanghyuk; Hammar, Arvid; Jeong, Byeongjoon; Kim, Geon Hee; Lee, Hyoungkwon; Kim, Dae Wook; Pak, Soojong

doi:10.1088/1538-3873/ab7547

Cited by 10 publications

(4 citation statements)

References 38 publications

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“…Figure 1 shows the configuration of the K-DRIFT pathfinder. It was designed as a linear astigmatism free-three mirror system (LAF-TMS) that is an all-reflective imaging system consisting of three free-form mirrors (see Chang 2013;Park et al 2020). The off-axis design can minimize the loss and scattering of light due to not requiring the internal structures located on the optical path.…”

Section: Telescopementioning

confidence: 99%

Performance Assessment of the KASI-Deep Rolling Imaging Fast-optics Telescope Pathfinder

Byun¹,

Ko²,

Kim³

et al. 2022

PASP

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In a ΛCDM universe, most galaxies evolve by mergers and accretions, leaving faint and/or diffuse structures, such as tidal streams and stellar halos. Although these structures are a good indicator of galaxies’ recent mass assembly history, they have the disadvantage of being difficult to observe due to their low surface brightness (LSB). To recover these LSB features by minimizing the photometric uncertainties introduced by the optical system, we developed a new optimized telescope named K-DRIFT pathfinder, adopting a linear astigmatism free-three mirror system. Thanks to the off-axis design, it is expected to avoid the loss and scattering of light on the optical path within the telescope. To assess the performance of this prototype telescope, we investigate the photometric depth and capability to identify LSB features. We find that the surface brightness limit reaches down to μ r,1σ ∼ 28.5 mag arcsec−2 in 10″ × 10″ boxes, enabling us to identify a single stellar stream to the east of NGC 5907. We also examine the characteristics of the point-spread function (PSF) and find that the PSF wing reaches a very low level. Still, however, some internal reflections appear within a radius of ∼6′ from the center of sources. Despite a relatively small aperture (0.3 m) and short integration time (2 hr), this result demonstrates that our telescope is highly efficient in LSB detection.

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Section: Telescopementioning

confidence: 99%

Performance Assessment of the KASI-Deep Rolling Imaging Fast-optics Telescope Pathfinder

Byun¹,

Ko²,

Kim³

et al. 2022

PASP

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“…Before optimization of the freeform surface, the rotational symmetry of the system was broken by tilting the secondary and tertiary mirrors about their foci to make the system free of linear astigmatism. A linear-astigmatism free three mirror system (LAF-TMS) has been shown by Park et al 9 to be an excellent starting point for freeform designs by using the mirror tilt angles and inter-mirror distances (Eq 2) to mitigate a dominating aberration early in the design process.…”

Section: Optical Design -On-axis Vs Off-axis Implementationsmentioning

confidence: 99%

The Versatile CubeSat Telescope: Going to Large Apertures in Small Spacecraft

Ashcraft¹,

Douglas²,

Kim³

et al. 2021

Preprint

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The design of a CubeSat telescope for academic research purposes must balance complicated optical and structural designs with cost to maximize performance in extreme environments. Increasing the CubeSat size (eg. 6U to 12U) will increase the potential optical performance, but the cost will increase in kind. Recent developments in diamond-turning have increased the accessibility of aspheric aluminum mirrors, enabling a cost-effective regime of well-corrected nanosatellite telescopes. We present an all-aluminum versatile CubeSat telescope (VCT) platform that optimizes performance, cost, and schedule at a relatively large 95 mm aperture and 0.4 degree diffraction limited full field of view stablized by MEMS fine-steering modules. This study features a new design tool that permits easy characterization of performance degradation as a function of spacecraft thermal and structural disturbances. We will present details including the trade between on-and off-axis implementations of the VCT, thermal stability requirements and finite-element analysis, and launch survival considerations. The VCT is suitable for a range of CubeSat borne applications, which provides an affordable platform for astronomy, Earth-imaging, and optical communications.

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“…The optical imaging system design based on the Linear Astigmatism Free-Three Mirror System (LAF-TMS) with freeform mirrors can reduce the off-axis aberrations in the focal plane and perform full-field diffraction-limited imaging with a wide field of view. 9 The LAF-TMS has been verified in space and UAV mission applications, showing that the reflective system has a degree of freedom in spectral bandwidth and system volume. 10,11 In this paper, we model and analyze the LAF-TMS with freeform mirror surface using the Photon Simulator PhoSim, which provides Monte-Carlo-based photon ray trace simulation imaging results.…”

Section: Introductionmentioning

confidence: 98%

Wide-wide linear astigmatism free-three mirror system (LAF-TMS) enabling wide field-of-view and spectral bandwidth detection

Kim

Han

et al. 2023

Advanced Optics for Imaging Applications: UV Through LWIR VIII

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The conventional on-axis reflective systems suffer from a diffraction effect on the Point Spread Function (PSF) due to the secondary mirror obscuration. Meanwhile, the unobscured off-axis reflective systems' imaging performance may be impacted by linear astigmatism aberration. The Linear Astigmatism Free-Three Mirror System (LAF-TMS) is a confocal off-axis reflective system that eliminates linear astigmatism and enables a wide Field of View (FoV). We present an enhanced design of LAF-TMS, called "wide-wide", which has an aperture of D=40mm, an effective focal length of f=75mm, and a wide FoV of 8.25 • (Horizontal) × 6.21 • (V ertical) combined with a wide spectral bandwidth capability suitable for Unmanned Aerial Vehicle (UAV) applications. To evaluate the performance of this compact and fast optical system design, we use the Photon Simulator (PhoSim) to model physically accurate PSF under different conditions of the mirror surface, mechanical environment, and atmosphere. As a benchmark, we compare and analyze the PhoSim PSF results with other ray tracing software such as Zemax and CodeV. Additionally, PhoSim is capable of simulating infrared spectral imaging cases with a user-defined Spectral Energy Distribution (SED), intensity, and emissivity of each pixel. The comprehensive simulation results demonstrate the high performance of the LAF-TMS with a wide-wide FoV and multispectral capabilities.

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Development of Linear Astigmatism Free—Three Mirror System (LAF-TMS)

Cited by 10 publications

References 38 publications

Performance Assessment of the KASI-Deep Rolling Imaging Fast-optics Telescope Pathfinder

Performance Assessment of the KASI-Deep Rolling Imaging Fast-optics Telescope Pathfinder

The Versatile CubeSat Telescope: Going to Large Apertures in Small Spacecraft

Wide-wide linear astigmatism free-three mirror system (LAF-TMS) enabling wide field-of-view and spectral bandwidth detection

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