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.