Class Julian

java.lang.Object
skyview.geometry.CoordinateSystem
skyview.geometry.csys.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
  • Field Summary

    Fields inherited from class skyview.geometry.CoordinateSystem

    B1950, Gal, ICRS, J2000
  • Constructor Summary

    Constructors 
    Constructor Description
    Julian​(double epoch)
    Get a Julian CoordinateSystem of a given epoch.
  • Method Summary

    Modifier and Type Method Description
    java.lang.String getDescription()
    Get a description of the object.
    java.lang.String getName()
    Get the name of this object.
    Rotater getRotater()
    Return the rotation associated with the coordinate system.
    Rotater precession()
    Get the Julian Precession Matrix for a given epoch (from J2000).

    Methods inherited from class skyview.geometry.CoordinateSystem

    factory, factory, getSphereDistorter

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • 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 Details

    • 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
    • getRotater

      public Rotater getRotater()
      Return the rotation associated with the coordinate system.
      Specified by:
      getRotater in class CoordinateSystem
    • 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.