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Астронет: Астрономическая картинка дня Двадцать полных Лун http://variable-stars.ru/db/msg/1219130/eng |
Credit & Copyright: Laurent Laveder
(PhotoAstronomique.net)
Explanation:
In celebration of tonight's
Full Moon,
the first of 2007,
consider this grid of twenty Full Moons.
From upper left to lower right, the images represent every
lunation
from May 2005 through December 2006.
The consecutive Full Moons are all shown at the
same scale, so
unlike the famous Moon Illusion the
change in apparent size seen here is real.
(For example, compare early and late 2006 Full Moons.)
The change is caused by
the
variation in lunar distance due to the
Moon's significantly non-circular orbit.
A subtler change in appearance can also be noticed
on close examination, as the Moon seems to wobble and rock slightly
from one Full Moon to the next.
This effect, known as
libration, is
more dramatic and easier
to see in a
twenty
frame movie comparing these twenty Full Moons.
APOD Editor to Discuss "Best
of APOD 2006" Pictures in NYC on January 5
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.