Solar eclipses occur when the Moon passes between the Earth and Sun
so that the Moons shadow falls on the Earth. Although solar
eclipses are rarely seen at any given location on Earth, they can be
observed somewhere on the Earths surface at least twice and as often
as five times per year. Eclipses can be observed by most Earth-orbiting
satellites that have wide fields of view. Therefore, scientists working
with data sets derived from these satellite sensors should be aware of the
reduced solar irradiance within the area of the Moons shadow.
This true-color Moderate-resolution Imaging Spectroradiometer (MODIS)
image shows a composite of two adjacent viewing swaths acquired on
December 25, 2000 in two consecutive overpasses. The scene covers an area
from the Great Lakes in the north to Georgia toward the south. (The full scene covers
from Northern Quebec to Florida). Notice that
the swath on the left side of the image [acquired at 17:30 UTC (12:30 EST)] is
considerably darker than the swath on the right [acquired at 15:50 UTC (10:50 EST)_eclips]
due to the Moons shadow.
This eclipse was partial (there was no place on Earth where the Sun was
completely hidden behind the Moon). The greatest eclipse occurred in Baffin
Island, north of this image, with a maximum eclipse magnitude of 0.72 (72% of
the Sun was screened by the Moon at that location). The Moons shadow
(penumbra) extended as far as Nicaragua, much further south of this image. The
penumbra covered an area of more than 12000 km diameter on Earth.
Image courtesy Jacques Descloitres, MODIS Land Group, NASA Goddard
Space Flight Center