直壁

C.L.Chan

在雲海旁邊是著名的直壁, 與月亮南部山區的交界 , 有一道長120 km (10個香港島由東至西的距離 ), 高300到400 m , 從前認為它是個懸崖峭壁 , 後來的觀測證實它應是個傾斜約15度的大斜坡 . 圖中還見月溪 Rupes Recta.

Straight Wall, length 120 km, height 300~400 m, with RupesRecta on Southern Part of The Moon, UT2021 04 21, 14h27m, Telescope TEC Maksutov-Cassegrain MC200/20, D=20cm,F.L.=400cm, Losmandy G-11 Equatorial Mount with motor drive. Camera QHY 5III224 Color Cam, Capture with FireCapture, Shoot at Gamma=100, Gain=37 Expo=0.413 ms/frame, avi format, stack and process 50% best frames in 1804 frames byfree Software AutoStakkert 3, wavelet with RegiStax V.6, Final touch byMicrosoft Photo software. Atmospheric condition: Transparent: 9/10, Seeing:8/10. Equipment borrowed from Mr. Ng. The photo was taken at Kennedy Town 堅尼地城, Hong Kong.