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Credit & Copyright: Anthony Ayiomamitis
(TWAN)
Explanation:
Today, the Sun crosses
the celestial equator heading south at 20:44 Universal Time.
An equinox (equal night), this astronomical event marks the
first day of autumn in the northern hemisphere and spring in the south.
With the Sun on the celestial equator, Earth
dwellers will experience
nearly 12
hours of daylight and 12 hours of darkness.
To celebrate, consider
this
remarkable record of the Sun's yearly journey
through planet Earth's sky, made with planned multiple exposures
captured on a single piece of 35 millimeter film.
Exposures were made at the same time of day
(9:00am local time), capturing the Sun's position on dates from
January 7 through December 20, 2003.
The multiple suns trace an intersecting curve
known as
an analemma.
A foreground base exposure of the
Temple
of Apollo in ancient Corinth, Greece,
appropriate for an analemma,
was digitally merged with the film image.
Equinox dates correspond to the middle points
(not the intersection point)
of
the analemma.
The curve is oriented at the corresponding direction
and altitude for the temple,
so the Sun's position for the September equinox is at the
upper midpoint near picture center.
Summer and winter solstices are at analemma top and bottom.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: analemma
Publications with words: analemma
See also: