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Астронет: Астрономическая картинка дня Цифровое лунное затмение http://www.variable-stars.ru/db/msg/1833053/eng |
Credit & Copyright: Michael Cain
Explanation:
Recorded on May 15/16 this sequence of exposures
follows the Full Moon during a total lunar eclipse as it arcs
above treetops in the clearing skies of central Florida.
A frame taken every 5 minutes by a digital camera
shows the progression of the eclipse over three hours.
The bright lunar disk grows dark and red as it
glides
through planet Earth's shadow.
In fact, counting the central frames in the sequence
measures the roughly 90 minute
duration of the total phase of this eclipse.
Around 270 BC, the Greek astronomer
Aristarchus
also measured the duration of total lunar eclipses,
but probably
without
the benefit
of digital watches and cameras.
Still,
using geometry he
devised a simple and impressively accurate way to calculate
the Moon's distance in terms of the radius of
planet Earth,
from the eclipse duration.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.