410
Prof. de Sitter, On the bearing of the Principle
LXXI. 5,
The orbit thus remains fixed and plane after the transformation. Since
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we find easily
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(40)
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If
and
are the longitude and latitude of the positive half of the axis of the transformation we have—
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If the plane to be transformed is the plane of (
) itself, we have in the system (
)
. The transformed position of the plane is then defined by
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or
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(41)
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Let the plane of (
) be the ecliptic, and consider another plane of which the inclination and node in the system (
) are
and
. In the system (
) its inclination and node on the plane of (
) are
and
, as given by the formulæ (40). Let its inclination on the transformed ecliptic be
. Taking unity for the denominator of
in (41) we find easily—
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or
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If the transformed plane be the equator, we have—
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