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Re: (meteorobs) OT (2nd. Try): The November 8, 2003 Lunar Eclipse
In a message dated 11/14/03 1:42:24 PM Eastern Standard Time,
unclefireballmtf@yahoo.com writes:
<< 1. I was under the allusion that the recent eclipse
was a total one. However, during "totality", I kept
noticing that the bottom edge of the moon was
brighter than all of the rest, particularly from the
bottom left if I remember right. It never seemed to
have been completely eclipsed. Is that possible or
what was I seeing?
The Earth's umbral shadow is not uniformly dark. The region around the rim
of the shadow tends to be somewhat brighter than that region at or near the
center of the shadow. Since this was a relatively short totality, with the Moon
skimming through the southernmost part of the umbra (the Moon's southern edge
was tucked inside the shadow by only about 50 miles), the lower rim tended to
appear noticeably brighter than the central and upper portions of the Moon.
Another factor is atmospheric refraction which allowed sunlight to be more
readily bent or refracted into the shadow and then on to the Moon.
2. Sometime after 1:10 UT, I peered through the
telescope (looking for the first signs of
"emergence") at the bottom, bright region mentioned
above and noted that the bottom "right" edge seemed to
be brighter than the left. What does one make of
that?
Mid totality was at 1:19 UT. Prior to that time, the lower right limb of the
Moon would appear brightest. After 1:19 UT, it would be the lower left limb
would appear brightest. The bright rim would appear to "pivot" along the
bottom edge of the Moon from right to left as the totally eclipsed Moon progressed
through the Earth's umbra.
-- joe rao
>>
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