Class Julian

  • All Implemented Interfaces:
    java.io.Serializable, Component

    public class Julian
    extends CoordinateSystem
    implements Component
    The class defining Julian coordinate systems. The reference coordinate system is J2000. We use the FK5 coordinate frame as the realization of the Julian coordinate system. At the 50 milliarcsecond level this is not valid: There is an offset of J2000 and FK5. However the details of this offset are still somewhat unclear, so we use the better defined frame.
    See Also:
    Serialized Form
    • Constructor Detail

      • Julian

        public Julian​(double epoch)
        Get a Julian CoordinateSystem of a given epoch.
        Parameters:
        epoch - The epoch of the equinox of the coordinates in calendar years (possibly fractional).
    • Method Detail

      • getName

        public java.lang.String getName()
        Get the name of this object.
        Specified by:
        getName in interface Component
      • getDescription

        public java.lang.String getDescription()
        Get a description of the object.
        Specified by:
        getDescription in interface Component
      • precession

        public Rotater precession()
        Get the Julian Precession Matrix for a given epoch (from J2000). Approach based on P.Wallace's SLA library. The equations are available in Kaplan, USNO Circular 163, 1981, page A2. Here we assume in these equations we assume T=0 so that we are doing a transformation between J2000 and the specified ending epoch.