Description
Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the target CelestialObject's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the target CelestialObject is modeled as a point.
The cardinal points, as a function of the alpha angle, are defined as:
- Noon (alpha angle = 0)
- Dusk (alpha angle = 90)
- Midnight (alpha angle = 180)
- Dawn (alpha angle = 270)
The mathematical definition of the alpha angle is:
![](embim41.gif)
Below is a diagram depicting how the alpha angle is defined:
![A visual representation of the Alpha angle. A visual representation of the Alpha angle.](cardinalpoints_alphaanglevisual.png) A visual representation of the Alpha angle.
Timing Precision Mode
This page describes functionality in nanosecond timing precision mode.
Click here to see the documentation for this object in millisecond timing precision mode.
Overload List
Signatures
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Return Value
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Description
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Spacecraft.CardinalPoints()
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String
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Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the Sun's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the Sun is modeled as a point.
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Spacecraft.CardinalPoints(CelestialObject target)
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String
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Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the target CelestialObjects's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the target CelestialObject is modeled as a point.
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Spacecraft.CardinalPoints(TimeSpanArray EventTime, Array EventType)
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Variable
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Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the Sun's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the Sun is modeled as a point.
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Spacecraft.CardinalPoints(CelestialObject target, TimeSpanArray EventTime, Array EventType)
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Variable
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Returns the times when the Spacecraft is at each of the cardinal points. The cardinal point calculations are based on the alpha angle, which is the angle between the Spacecraft's position and the target CelestialObjects's position with respect to the Spacecraft's central body when both vectors are projected onto the Spacecraft's orbit plane. Note that the target CelestialObject is modeled as a point.
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See also
Spacecraft Object
Spacecraft.SpacecraftNoon
Spacecraft.SunTerminatorCrossingTimes
Spacecraft Propagation Guide
Coverage and Contact Analysis Guide
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