The Korea Astronomy and Space Science Institute (KASI) has been developing a next-generation coronagraph (NGC) in cooperation with NASA to measure the coronal electron density, temperature, and speed simultaneously, using four different optical filters around 400 nm. KASI organized an expedition to demonstrate the coronagraph measurement scheme and the instrumental technology during the 2017 total solar eclipse (TSE) across the USA. The observation site was in Jackson Hole, Wyoming, USA. We built an eclipse observation system, the Diagnostic Coronal Experiment (DICE), composed of two identical telescopes to improve the signal-to-noise ratio. The observation was conducted at four wavelengths and three linear polarization directions in the limited total eclipse time of about 140 seconds. We successfully obtained polarization data for the corona but we were not able to obtain information on the coronal electron temperature and speed due to the low signal-to-noise ratio of the optical system and strong emission from prominences located at the western limb. In this study, we report the development of DICE and the observation results from the eclipse expedition. TSE observation and analysis with our self-developed instrument showed that a coronagraph needs to be designed carefully to achieve its scientific purpose. We gained valuable experience for future follow-up NASA-KASI joint missions: the Balloon-borne Investigation of the Temperature and Speed of Electrons in the Corona (BITSE) and the COronal Diagnostic EXperiment (CODEX).

Introduction
DICE Development
    Optics Design
    Filter and Polarizer System
    Baffle Design
Instrument Test
    Resolution and Stray Light Test
    Polarizer Angle Test
    Operations and Data Acquisition 
    System Tolerances and Image Stacking
Observation
    2017 TSE Experiment
    Data Analysis
Results 
Discussion 
Acknowledgments
References

• Kyung-Suk Cho(Korea Astronomy and Space Science Institute/University of Science and Technology) Corresponding author
• Heesu Yang(Korea Astronomy and Space Science Institute)
• Jae-Ok Lee(Korea Astronomy and Space Science Institute)
• Su-Chan Bong(Korea Astronomy and Space Science Institute)
• Jihun Kim(Korea Astronomy and Space Science Institute)
• Seonghwan Choi(Korea Astronomy and Space Science Institute)
• Jongyeob Park(Korea Astronomy and Space Science Institute)
• Kyuhyoun Cho(Astronomy Program, Department of Physics and Astronomy, Seoul National University)
• Ji-Hye Baek(Korea Astronomy and Space Science Institute)
• Yeon-Han Kim(Korea Astronomy and Space Science Institute)
• Young-Deuk Park(Korea Astronomy and Space Science Institute)