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99:. This is the geocentric, normal plane of the shadow axis. In other words, it is the plane through the Earth's center that is perpendicular to the line through the centers of the occulting and the occulted bodies. One advantage, among others, of choosing this plane is that the outline of the shadow on it is always a circle, and there is no
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The basic concept is that
Besselian elements describe the movement of the shadow cast by the occulting body – for solar eclipses this is the shadow of the Moon – on a specifically chosen plane, called the
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on the Earth's surface, and hence the circumstances of the eclipse at a specific location. This method was developed in the 1820s by the German mathematician and astronomer,
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Comparatively few values are needed to accurately describe the movement of the shadow on the fundamental plane. Based on this, the next step is to
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measures how much that rotation has slowed over time and must also be taken into account when predicting local eclipse circumstances.
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on the Earth's surface will experience an eclipse are determined by the Earth's rotation. A variable called
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a similar method is used, in which the shadow is cast on the Moon instead of the Earth.
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Although the
Besselian elements determine the overall geometry of an eclipse, which
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For solar eclipses, the
Besselian elements are used to calculate the path of the
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are a set of values used to calculate and predict the local circumstances of
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the shadow cone on to the Earth's surface, taking into account the
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for an observer on Earth. This method is particularly used for
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Seidelmann, P. Kenneth; Urban, Sean E., eds. (2013).
164:Explanatory Supplement to the Astronomical Almanac
228:A manual of spherical and practical astronomy.
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231:J. B. Lippincott & Co, Philadelphia 1863
215:Cambridge University Press, Cambridge 1985,
166:(3rd ed.). University Science Books.
48:, but is also applied for occultations of
196:Canon of solar eclipses: -2003 to +2526
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28:on Earth's surface and in
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198:. Astronomisches Büro.
101:perspective distortion
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118:, and the observer's
24:(green) during total
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213:Spherical astronomy.
255:Celestial mechanics
225:William Chauvenet:
112:figure of the Earth
72:. In addition, for
81:umbra and penumbra
38:Besselian elements
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22:umbra and penumbra
173:978-1-891389-85-6
97:fundamental plane
89:William Chauvenet
30:fundamental plane
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211:Robin M. Green:
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85:Friedrich Bessel
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192:Meeus, Jean
20:Outline of
239:Categories
145:References
135:longitudes
128:elevation
124:longitude
245:Eclipses
194:(1992).
120:latitude
116:rotation
62:transits
108:project
70:Mercury
56:by the
54:planets
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114:, its
66:Venus
50:stars
32:(red)
217:ISBN
168:ISBN
126:and
60:and
58:Moon
36:The
68:or
64:of
52:or
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152:^
139:ΔT
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