Dr. Seonghwan Choi Profile

Dr. Seonghwan Choi

Principal Researcher at Korea Astronomy and Space Science Institute

SPIE Involvement:

Author

Websites:

Company Website

Publications (15)

Proceedings Article | 23 August 2024 Poster + Paper

Poster + Paper

Polarimetric characterization of the coronal diagnostic experiment (CODEX)

Marta Casti, Jeffrey Newmark, Yeon-Han Kim, Gerardo Capobianco, Hervé Haudemand, Donguk Song, Sung-Hong Park, Su-Chan Bong, Kyungsuk Cho, Seonghwan Choi, Qian Gong, Ji-Hye Baek, Jongyeob Park, Jihun Kim, Heesu Yang, Nelson Reginald, Nicholeen Viall, Silvano Fineschi, Federico Landini, Davide Loreggia, Luca Zangrilli, Lucia Abbo, Jason Budinoff

Proceedings Volume 13092, 130927O (2024) https://doi.org/10.1117/12.3020730

KEYWORDS: Polarization, Coronagraphy, Equipment, Polarimetry, Sensors, Demodulation, Polarized light, Modulation, Linear polarizers, Polarization imaging

Read Abstract +

Proceedings Article | 23 August 2024 Poster + Paper

Poster + Paper

Test results of GrainCams EQM payload for the CLPS lunar rover

Woojin Kim, Bongkon Moon, Dukhang Lee, Dae-Hee Lee, Minbae Kim, Minsup Jeong, Jihun Kim, Sung-joon Park, Yunjong Kim, Seonghwan Choi, Jehyuck Shin, Mingyeong Lee, Seul-Min Baek, Chae Kyung Sim, Young-Jun Choi, Sungsoo Kim

Proceedings Volume 13092, 130927B (2024) https://doi.org/10.1117/12.3019741

KEYWORDS: Vibration, Modulation transfer functions, Reliability, Vacuum, Particles, Mechanical engineering

Read Abstract +

Proceedings Article | 23 August 2024 Presentation + Paper

Presentation + Paper

CODEX optical design and alignment

Qian Gong, Jeffrey Newmark, Yeon-Han Kim, Marta Casti, Lucia Abbo, Ji-Hye Baek, Su-Chan Bong, Jason Budinoff, Gerado Capobianco, Kyungsuk Cho, Seonghwan Choi, Silvano Fineschi, Hervé Haudemand, Jihun Kim, Federico Landini, Davide Loreggia, Sung-Hong Park, Jongyeob Park, Nelson Reginald, Donguk Song, Heesu Yang, Luca Zangrilli

Proceedings Volume 13092, 130922I (2024) https://doi.org/10.1117/12.3020705

KEYWORDS: Diffraction, Coronagraphy, Optical alignment, Telescopes, Stray light, Cameras, Vignetting, Optical design

Read Abstract +

The COronal Diagnostic EXperiment (CODEX) is a Heliophysics mission to measure the density, temperature, and velocity of the electrons in the solar corona with the primary goal of improving our understanding of the physical conditions of the solar wind in the acceleration region. The temperature and velocity measurement requires much higher signal-to-noise ratio than the density measurements. In solar coronagraphs, the diffraction of the solar disk light due to the occulting element is the dominant source of noise. Therefore, to further suppress the diffracted sun light with respect to the existing coronagraphs is a critical element of the CODEX design. To minimize the stray light due to diffraction, the selected optical design is a two-stage standard coronagraph with an external occulter, an internal occulter, and a Lyot stop. What is unique for this design is that a focal mask was inserted at the telescope focal plane. It works together with the field lens suppressing the stray light down by ~ another order of magnitude as compared to a traditional three-stage approach. During the optical design, a Fourier Transform based beam propagation software, i.e., GLAD, was used to model the beam path through the full coronagraph, from the external occulter to the detector array. All diffraction sensitive elements: external occulter, internal occulter, focal mask, and Lyot stop were carefully modeled and optimized. As a result, the requirement of achieving a stray light level which is one order of magnitude lower than F-corona was satisfied. On the other hand, to achieve the final suppression, a precision optical alignment is another must. This paper also presents our creative alignment procedure: using the combination of metrology, precision alignment equipment, and real time diffraction ring monitoring to minimize the diffraction. The final test results show that the suppression ratio (B/B0) reaches 10-11 level, which is equivalent to one order of magnitude lower than F-corona.

Proceedings Article | 17 June 2024 Presentation + Paper

Presentation + Paper

Stray light analysis for the SurfCam

Jihun Kim, Minsup Jeong, Minbae Kim, Young-Jun Choi, Sungsoo Kim, Dukhang Lee, Bongkon Moon, Dae-Hee Lee, Seonghwan Choi, Chae Kyung Sim, Jehyuck Shin, Seul-Min Baek, Mingyeong Lee

Proceedings Volume 13019, 1301905 (2024) https://doi.org/10.1117/12.3016902

KEYWORDS: Stray light, Stray light analysis, Signal to noise ratio, Sensors, Scattered light, Lenses, Light scattering, Optomechanical design, Incident light

Read Abstract +

Proceedings Article | 11 March 2024 Presentation + Paper

Presentation + Paper

Current status of SurfCam development

Jihun Kim, Minsup Jeong, Minbae Kim, Youngju Kim, Young-Jun Choi, Sungsoo Kim, Dukhang Lee, Bongkon Moon, Dae-Hee Lee, Seonghwan Choi, Chae Kyung Sim, Jehyuck Shin, Seul-Min Baek, Mingyeong Lee

Proceedings Volume 12893, 1289302 (2024) https://doi.org/10.1117/12.3002168

KEYWORDS: Optical design, Modulation transfer functions, Design, 3D image processing, Cameras, Optics manufacturing, Microlens array, 3D metrology, Windows, Testing and analysis

Read Abstract +

Proceedings Article | 5 October 2023 Presentation

Presentation

Unveiling new frontiers: conceptual design of optical and EUV telescopes with instruments for the L4 mission

Jeong-Yeol Han, Jeongyeop Park, Sung-Hong Park, Eun-Kyung Lim, Donguk Song, Kyung-Suk Cho, Junga Hwang, Seonghwan Choi, Rok-Soon Kim, Jungjoon Seough, JongDae Sohn, Jihun Kim

Proceedings Volume 12676, 126760L (2023) https://doi.org/10.1117/12.2677366

KEYWORDS: Telescopes, Extreme ultraviolet, Design and modelling, Equipment, EUV optics, Space weather, Solar processes, Remote sensing, Optical telescopes, Magnetism

Read Abstract +

Proceedings Article | 4 October 2023 Poster + Paper

Poster + Paper

Preliminary mechanical design of GrainCams payload for the CLPS lunar rover

Woojin Kim, Bongkon Moon, Dukhang Lee, Dae-Hee Lee, Min-Bae Kim, Minsup Jeong, Jihun Kim, Seonghwan Choi, Jehyuck Shin, Mingyeong Lee, Seul-Min Baek, Chae Kyung Sim, Young-Jun Choi, Sungsoo Kim

Proceedings Volume 12677, 126770R (2023) https://doi.org/10.1117/12.2677855

KEYWORDS: Safety, Contact lenses, Design and modelling, Modal analysis, Interfaces, Thermal analysis, Lenses, Structural analysis, Vibration, Temperature metrology

Read Abstract +

Proceedings Article | 4 October 2023 Poster + Paper

Poster + Paper

On-orbit thermal control system design and analysis for space optical telescope ROKITS

Jaegun Yoo, Jeong-Yeol Han, Hui-Kyung Kim, Woo Kyoung Lee, Seonghwan Choi, Dukhang Lee, Chanhaeng Lee, Daewook Kim

Proceedings Volume 12676, 1267611 (2023) https://doi.org/10.1117/12.2676760

KEYWORDS: Thermal analysis, Design and modelling, Thermal modeling, Fused deposition modeling, Solar energy, Optical telescopes, Optical surfaces, Space operations, Satellites, Control systems

Read Abstract +

Proceedings Article | 4 October 2023 Presentation + Paper

Presentation + Paper

Optical design and analysis of the ROKITS cameras

Jihun Kim, Youngju Kim, Seonghwan Choi, Dukhang Lee, Gwanghui Jeong, Jongyeob Park, Ji-Hye Baek, Yunjong Kim, Tae-Yong Yang, Jaeheung Park, Kyoung-min Roh, Young-Sil Kwak, Chanhaeng Lee, Jong-Kyun Chung, Woo kyoung Lee

Proceedings Volume 12676, 126760U (2023) https://doi.org/10.1117/12.2676608

KEYWORDS: Optical design, Cameras, Tolerancing, Optical filters, Modulation transfer functions, Earth's atmosphere, Sensors, Atmospheric sciences, Auroras

Read Abstract +

Proceedings Article | 8 March 2023 Presentation + Paper

Presentation + Paper

Design and analysis of the light field camera for SurfCam

Jihun Kim, Minsup Jeong, Min Bae Kim, Youngju Kim, Young-Jun Choi, Sungsoo Kim, Dukhang Lee, Bongkon Moon, Dae-Hee Lee, Seonghwan Choi, Chae Kyung Sim, Mingyeong Lee, Jehyuck Shin

Proceedings Volume 12428, 1242803 (2023) https://doi.org/10.1117/12.2646524

KEYWORDS: Modulation transfer functions, Optical design, Windows, Lenses, Design and modelling, Transmittance, Tolerancing, Glasses, Coating, Cameras

Read Abstract +

Proceedings Article | 29 August 2022 Poster

Poster

Design and analysis of the SiC solar telescope for extreme environments

Jihun Kim, Seonghwan Choi, Jeong-Yeol Han, Yunjong Kim, Ji-Hye Baek, Jongyeob Park, Heesu Yang, Sujin Kim, Young-Soo Kim, Jaegun Yoo, Youra Jun, Bi-Ho Jang, Il Kweon Moon, Dohoon Kim, Minkyum Kim, Gwanghui Jeong, Myung Cho

Proceedings Volume 12182, 1218233 (2022) https://doi.org/10.1117/12.2628857

KEYWORDS: Solar telescopes, Optical instrument design, Silicon carbide, Telescopes, Mirrors, Bridges, Off axis mirrors, Light scattering, Tolerancing, Temperature metrology

Read Abstract +

Proceedings Article | 19 September 2017 Presentation

Presentation

Development of the camera lens system for total solar eclipse observation (Conference Presentation)

Jihun Kim, Seonghwan Choi, Ji-Hye Beck, Jongyeob Park, Su-Chan Bong, Bi-Ho Jang, Heesu Yang, Jinho Kim, Geon-Hee Kim, Kyungsuk Cho, Sung-Joon Park

Proceedings Volume 10401, 104010Q (2017) https://doi.org/10.1117/12.2272190

KEYWORDS: Cameras, Imaging systems, Polarizers, Bandpass filters, CCD cameras, Astronomy, Coronagraphy, Image quality, Optical engineering, Analytical research

Read Abstract +

Proceedings Article | 7 August 2014 Paper

Paper

AO-308: the high-order adaptive optics system at Big Bear Solar Observatory

Sergey Shumko, Nicolas Gorceix, Seonghwan Choi, Aglaé Kellerer, Wenda Cao, Philip Goode, Volodymyr Abramenko, Kit Richards, Thomas Rimmele, Jose Marino

Proceedings Volume 9148, 914835 (2014) https://doi.org/10.1117/12.2056731

KEYWORDS: Digital signal processing, Adaptive optics, Cameras, Mirrors, Wavefronts, Signal processing, Observatories, Image processing, Actuators, Telescopes

Read Abstract +

Proceedings Article | 15 July 2008 Paper

Paper

Development of a correlation tracker system for the New Solar Telescope

Seonghwan Choi, Jakyoung Nah, Yong-Jae Moon, Haimin Wang, Roy Coulter

Proceedings Volume 7015, 701553 (2008) https://doi.org/10.1117/12.788661

KEYWORDS: Mirrors, Cameras, Digital signal processing, Computer programming, Solar telescopes, CMOS cameras, Motion measurement, Signal processing, Computed tomography, Imaging systems

Read Abstract +

Proceedings Article | 27 June 2006 Paper

Paper

The telescope control system of the New Solar Telescope at Big Bear Solar Observatory

G. Yang, J. Varsik, S. Shumko, C. Denker, S. Choi, A. Verdoni, H. Wang

Proceedings Volume 6274, 62741Y (2006) https://doi.org/10.1117/12.672402

KEYWORDS: Telescopes, Control systems, Human-machine interfaces, Mirrors, Space telescopes, Telecommunications, Distributed computing, Solar telescopes, Observatories, Domes

Read Abstract +

Showing 5 of 15 publications

SIGN IN TO:

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Advertisement

Advertisement