Coverage of earthshine observations

Mean cloud cover map for 15th October 1999 (top) and 4th September 1999 (middle) over the area contributing to the earthshine during about 4 hours of observation from BBSO each night. The mean lunar phases were -115.8 degrees (waxing) and +109.7 degrees (waning), respectively. Such coverages are typical for a single night's observations. Bottom panel: The weighted contribution of each part of the Earth to the ES observations during the 1999-2001 period. The arbitrary normalized scale reflects the number of times that each area of the Earth has contributed to the earthshine, weighted by the Earth-Moon cosine at each observation. The darker blue areas are those we cannot see in the earthshine from California.
Download this image
Image credit: Earthshine Project, BBSO.