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Unformatted text preview: many available , x y ε ε Orbits in Three Dimensions Previously, we considered everything in 2D Now, try 3D problems some background necessary to define an orbit in space First, define coordinate systems (3D) to help Two basic types for us to use: (1) Ecliptic System – fundamental plane is the plane of the ⊕ ’s orbit about the Sun (latitude, longitude) (2) Equatorial System – Fundamental plane is the plane of the body’s equator (right ascension, declination) Obliquity of ecliptic ( ε ) – inclination of ecliptic with respect to the equator To effectively use a coordinate system, reference directions must be known and understood; we need a fixed reference direction in the fundamental plane from which measurements are made Æ vernal equinox I1 , x y x x ε = intersection of ecliptic and Earth equatorial planes I2 I2 I3 “precession of the equinoxes” – change in the direction of the Earth’s spin axis Caused by perturbing forces on its attitude, i.e., ☼ and e gravity...
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This note was uploaded on 12/22/2010 for the course A&AE 532 taught by Professor Kathleenhowell during the Spring '10 term at Purdue UniversityWest Lafayette.
 Spring '10
 KathleenHowell

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