EPOD - a service of USRA
The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.
Analemma from Albusciago, Italy
February 29, 2020
Analemma2016 (1)
Photographers: Paolo Bardelli; Luca Carlana
Summary Authors: Paolo Bardelli; Luca Carlana
Our Planet makes a complete turn around the Sun in 365.2422 days.
On average, one day (29 February) is added to the calendar every
4-years to catch up with this small delay. Like 2016, 2020 is a
leap year.
Four years ago, Luca and I decided to photograph the Sun every day at
noon (local time), from Albusciago, Italy. We were able to get 245 out
of 366 useful shots (67 percent). The sum of these images produces the
figure 8 form called an analemma. This is because the
Earth's orbit is elliptical and not circular, the speed is not
uniform ( Kepler's laws) and the rotation axis is inclined
by 23 degrees.
To photograph this analemma, we used a digital camera in an automated
fixed location with a programmable electronic board. From a fairly
complete analemma one can derive a considerable amount of information
(for example, the positions of equinoxes and solstices, the
symmetry of the seasons, etc.). The apparent motion of the Sun is
faster towards the Northern HemisphereΓÇÖs spring and autumn but is
almost zero in June.
Note that the path (apparent path) of our home star is in front of
the constellations of the Zodiac. By the way, there are 13
constellations of the Zodiac, not 12. The thirteenth constellation is
Ophiuchus, nestled between Scorpio and Sagittarius.
Photo Details: Canon 350d camera, zoom lens18/55 mm; 18 mm; with
Astrosolar filter. Sum of 245 images - 1/250 second exposure; f/5,6,
400 ISO; Photoshop CC (Windows). Hardware and processing: Paolo
Bardelli; Software: Luca Carlana.
* Albusciago, Italy Coordinates: 45.7395, 8.7939
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More...
Sun Links
* NASA Solar Dynamics Observatory
* NASA Solar Eclipse Page
* NOAA Solar Calculator
* The Sun-Earth Connection: Heliophysics
* The Sunspot Cycle
* Solar System Exploration: The Sun
* The Sun Now
* This WeekΓÇÖs Sky
-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.
https://epod.usra.edu
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