Image Details
Caption: Figure 4.
The upper (lower) panels show the twilight flat, photometric flat, and distribution map of the FWHM, respectively, for J (﹩{W}^{{\prime} }﹩) band. The dark spots in the J-band photometric flat are likely caused by ice crystals, while the striping in the ﹩{W}^{{\prime} }﹩-band photometric flat is correlated with the striping in the map of FWHM and may be introduced by the ﹩{W}^{{\prime} }﹩ filter, which will be inspected on the next expedition.
© 2026. The Author(s). Published by the American Astronomical Society.