反光的直壁

C.L.Chan

反光的直壁, 它是一道長120 km (10個香港島由東至西的距離 ), 高300到400 m 的斜坡, 面向西, 在月初, 陽光從東(右) 邊射過來, 直壁是黑色的. 但在下半的個月, 陽光從西(左) 邊射過來, 它就反射陽光呈白色, 不過你要夜半起床, 才看到這現象. 因當地陽光很低射來, 直壁旁邊的小隕坑更易現身.

Straight Wall, length 120 km, height 300~400 m, with RupesRecta on Southern Part of The Moon, UT 2021 06 02, 21h25m, Telescope TECMaksutov-Cassegrain MC200/20, D=20cm, F.L.=400cm, Losmandy G-11 EquatorialMount with motor drive. Camera QHY 5III 224 Color Cam, Capture withFireCapture, Shoot at Gamma=100, Gain=37 Expo= 0.513 ms/frame, avi format,stack and process 56% best frames in 1399 frames by free Software AutoStakkert3, wavelet with RegiStax V.6, Final touch by Microsoft Photo software.Atmospheric condition: Transparent: 8/10, Seeing: 8/10. Equipment borrowed fromMr. Ng. The photo was taken at Kennedy Town 堅尼地城,Hong Kong.