Diagrammatic representation of Sun's position over a period of time
For the book by Ptolemy, see Analemma (Ptolemy). For its more generic meaning as a graphical procedure, see Orthographic projection.
Afternoon analemma photo taken in 1998–99 in Murray Hill, New Jersey, USA, by Jack Fishburn. The Bell Laboratories building is in the foreground.Analemma with date marks, printed on a globe, Globe Museum, Vienna, Austria
In astronomy, an analemma (/ˌænəˈlɛmə/; from Ancient Greek ἀνάλημμα (analēmma) 'support')[a] is a diagram showing the position of the Sun in the sky as seen from a fixed location on Earth at the same mean solar time, as that position varies over the course of a year. The diagram will resemble a figure eight. Globes of Earth often display an analemma as a two-dimensional figure of equation of time vs. declination of the Sun.
The north–south component of the analemma results from the change in the Sun's declination due to the tilt of Earth's axis of rotation as it orbits around the Sun. The east–west component results from the nonuniform rate of change of the Sun's right ascension, governed by the combined effects of Earth's axial tilt and its orbital eccentricity.[1]
One can photograph an analemma by keeping a camera at a fixed location and orientation and taking multiple exposures throughout the year, always at the same time of day (disregarding daylight saving time).
Analemmas (in the modern sense of the term) have been used in conjunction with sundials since the 18th century to convert between apparent and mean solar time. Before this, the term had a more generic meaning that referred to a graphical procedure of representing three-dimensional objects in two dimensions, now known as orthographic projection.[2][3]
Although the term analemma usually refers to Earth's solar analemma, it can be applied to other celestial bodies as well.
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^Jenkins, Alejandro (2013). "The Sun's position in the sky". European Journal of Physics. 34 (3): 633–652. arXiv:1208.1043. Bibcode:2013EJPh...34..633J. doi:10.1088/0143-0807/34/3/633. S2CID 119282288.
^Sawyer, Frederick (June 1994). "Of Analemmas, Mean Time and the Analemmatic Sundial - Part 1" (PDF). Bulletin of the British Sundial Society. 6 (2): 2–6.
^Sawyer, Frederick (February 1995). "Of Analemmas, Mean Time and the Analemmatic Sundial - Part 2" (PDF). Bulletin of the British Sundial Society. 7 (1): 39–44.
In astronomy, an analemma (/ˌænəˈlɛmə/; from Ancient Greek ἀνάλημμα (analēmma) 'support') is a diagram showing the position of the Sun in the sky as seen...
figure-8. An analemma can be pictured by superimposing photographs taken at the same time of day, a few days apart for a year. An analemma can also be...
Orthographic projection (also orthogonal projection and analemma) is a means of representing three-dimensional objects in two dimensions. Orthographic...
Sun, and the Earth and Moon's paired revolutions around each other. The analemma can be used to make approximate predictions of the time of sunrise. In...
through the year, along with solar noon. These effects are plotted by an analemma. Neglecting atmospheric refraction and the Sun's non-zero size, whenever...
have done for a heliocentric one, presumably for didactic purposes. The Analemma is a short treatise where Ptolemy provides a method for specifying the...
inverse proportion of their masses. This system has been proposed for the Analemma Tower concept, which employs the system to suspend a building from a cable...
mean of zero. The equation of time is the east or west component of the analemma, a curve representing the angular offset of the Sun from its mean position...
globes have one celestial feature marked on them: a diagram called the analemma, which shows the apparent motion of the Sun in the sky during a year. Globes...
to the analemma. The dial of Brou in front of the church of Brou in Bourg-en-Bresse, France is an example of the erroneous use of the analemma in the...
Advanced Composition Explorer – NASA satellite of the Explorer program Analemma – Diagrammatic representation of Sun's position over a period of time Antisolar...
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in Orithena on an ancient analemma symbol within the excavation. (It is later revealed that Orolo had transmitted the analemma symbol to the spaceship and...
nighttime; the time step is 1 hour. Each "8" pattern in all figures is an analemma corresponding to a specific hour of every day of the year; all the 24 hours...
solar time is the equation of time, which can also be seen in Earth's analemma. As viewed from Earth during the year, the Sun appears to slowly drift...
object above the average surface of the Earth's oceans (mean sea level). Analemma a term in astronomy used to describe the plot of the positions of the Sun...
During 1978 and 1979 he was the first person to successfully photograph the analemma, making 48 separate exposures on a single piece of film during a 12-month...
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equation of time intersecting a time scale to display clock time directly. An analemma may be added to many types of sundials to correct apparent solar time to...
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Plus Sign and the Roundels Sable with a Minus Sign all counterchanged an Analemma palewise the small loop upwards Gules interlaced with three Arrows points...
course of a day traces out a path in the sky that is typically some form of analemma. A special case of geosynchronous satellite is the geostationary satellite...
in topology, the rose with two petals Figure 8, shape described by an analemma, a curve in astronomy Figure-eight knot (mathematics), in knot theory Lemniscate...
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