# SaturnRingSystem

``public struct SaturnRingSystem``

/ Saturn has many rings. Here we consider the ring system as a whole.

• ``` julianDay ```

Undocumented

#### Declaration

Swift

``public fileprivate(set) var julianDay: JulianDay { get }``
• ``` earthCoordinates ```

The Saturnicentric coordinates of the Earth referred to the plane of the ring (B)

#### Declaration

Swift

``public var earthCoordinates: SaturnicentricCoordinates { get }``
• ``` sunCoordinates ```

The Saturnicentric coordinates of the Sun referred to the plane of the ring (B)

#### Declaration

Swift

``public var sunCoordinates: SaturnicentricCoordinates { get }``
• ``` saturnicentricSunEarthLongitudesDifference ```

The difference between the Saturnicentric longitude of the Sun and the Earth, measured in the plane of the ring. Used to compute Saturn’s magnitude.

#### Declaration

Swift

``public var saturnicentricSunEarthLongitudesDifference: Degree { get }``
• ``` northPolePositionAngle ```

The position angle of the north pole of rotation of the planet. Because the ring is situated exactly in Saturn’s equator plane, P is also the geocentric position angle of the northern semiminor axis of the apparent ellipse of the ring, measured from the North towards the East (trust me… see AA p.317)

#### Declaration

Swift

``public var northPolePositionAngle: Degree { get }``
• ``` majorAxis ```

The major axis of the outer edge of the outer ring.

#### Declaration

Swift

``public var majorAxis: ArcSecond { get }``
• ``` minorAxis ```

The minor axis of the outer edge of the outer ring.

#### Declaration

Swift

``public var minorAxis: ArcSecond { get }``