Coronal Hole Study -- 2025

Special observation of disk cronal hole : 2025/09/11 2:03 UT- with XOB#1CE4 : 2025/09/11 timeline

In addition to Al_mesh and Al_poly, stray light subtraction for thin_Be was also applied!

for Al_poly/Al_mesh (orange): photon_noise_threshold = 0.20 (default value of xrt_teem).
for thin_Be/Al_poly (green): photon_noise_threshold = 0.60 (unable to measure CH,
i.e., black area was eliminated by xrt_teem due to low signal)