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Астронет: Астрономическая картинка дня Полуденная аналемма над Азербайджаном http://variable-stars.ru/db/msg/1294396/eng |
Credit & Copyright: Tunç Tezel
(TWAN)
Explanation:
Is the Sun always straight up at noontime?
No.
For example, the Sun never appears directly overhead from locations
well north or south of the Earth's equator.
Conversely, there is always a place on Earth where the Sun will appear at
zenith at noon -- for example on the equator during an
equinox.
Turning the problem around, however, as in finding where the Sun actually appears
to be at
high noon,
is as easy as waiting for midday, pointing your camera up, and taking a picture.
If you do this often enough,
you find that as the days march by, the Sun slowly traces out a figure eight on the
sky.
Pictured above
is one such high noon
analemma --
a series of pictures always taken at exactly noontime over the course of a year.
The above fisheye image, accumulated mostly during 2012,
also shows some buildings and trees of
Baku,
Azerbaijan around the edges.
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.