The goals for the Hi-C instrument were to image the solar EUV corona at a resolution of ~0.2 arcsec (~0.1 arcsec/pixel), an unmatched accomplishment by any prior observatory. This goal required highly polished mirrors with very tight figure tolerances, low scattering, and low camera noise. Short exposure times and high cadence were also desired for this observation set, especially for a short-duration rocket launch. An H-alpha camera is included for context pointing only.
Detailed information can be found in the instrument papers:
The High-Resolution Coronal Imager, Flight 2.1
Rachmeler et al. 2019, Solar Physics, 294, 174, 10.1007/s11207-019-1551-2
The High-Resolution Coronal Imager (Hi-C)
Kobayashi, K. et al. 2014, Solar Physics, 10.1007/s11207-014-0544-4