Class SkySystem


  • public abstract class SkySystem
    extends java.lang.Object
    Represents a sky coordinate system.

    Conversions all go via FK5 J2000.0, I think. SLALIB (Pal) is used to do the work. In some cases an epoch is considered. No opportunity is given for using an equinox value. I am not an expert on sky coordinate systems, and I think there may be subtleties which I'm not addressing accurately here.

    Since:
    30 Aug 2005
    Author:
    Mark Taylor
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected SkySystem​(java.lang.String name, java.lang.String description, java.lang.String ucd1, java.lang.String ucd2, java.lang.String descrip1, java.lang.String descrip2, java.lang.String colname1, java.lang.String colname2)
      Constructor.
    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      abstract double[] fromFK5​(double c1, double c2, double epoch)
      Converts from FK5 J2000.0 into this system.
      java.lang.String[] getCoordinateColumnNames()
      Returns labels suitable for use as column names in this system.
      java.lang.String[] getCoordinateDescriptions()
      Returns a full description of each coordinate in this system.
      java.lang.String[] getCoordinateNames()
      Returns names of the coordinates in this system.
      java.lang.String[] getCoordinateUcds()
      Returns a suitable UCD1+ for each coordinate in this system.
      java.lang.String getDescription()
      Returns a short description of this system.
      static SkySystem[] getKnownSystems()
      Returns an array of all the systems known.
      java.lang.String getName()
      Returns the name of this system.
      static SkySystem getSystemFor​(java.lang.String sysName)
      Returns a system which matches a given string.
      static java.lang.String getSystemUsage()
      Returns a snippet of XML which describes the systems and their meanings.
      abstract double[] toFK5​(double c1, double c2, double epoch)
      Converts to FK5 J2000.0 from this system.
      java.lang.String toString()  
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • ICRS

        public static final SkySystem ICRS
        ICRS system.
      • FK5

        public static final SkySystem FK5
        FK5 system.
      • FK4

        public static final SkySystem FK4
        FK4 system.
      • GALACTIC

        public static final SkySystem GALACTIC
        Galactic system.
      • SUPERGALACTIC

        public static final SkySystem SUPERGALACTIC
        Supergalactic system.
      • ECLIPTIC

        public static final SkySystem ECLIPTIC
        Ecliptic sysem.
    • Constructor Detail

      • SkySystem

        protected SkySystem​(java.lang.String name,
                            java.lang.String description,
                            java.lang.String ucd1,
                            java.lang.String ucd2,
                            java.lang.String descrip1,
                            java.lang.String descrip2,
                            java.lang.String colname1,
                            java.lang.String colname2)
        Constructor.
        Parameters:
        name - short system name
        description - a few words of description
        ucd1 - UCD1+ for first coordinate
        ucd2 - UCD1+ for second coordinate
        descrip1 - short description of first coordinate
        descrip2 - short description of second coordinate
        colname1 - label for first coordinate suitable for use as column name
        colname2 - label for second coordinate suitable for use as column name
    • Method Detail

      • fromFK5

        public abstract double[] fromFK5​(double c1,
                                         double c2,
                                         double epoch)
        Converts from FK5 J2000.0 into this system.
        Parameters:
        c1 - right ascension in FK5 (radians)
        c2 - declination in FK5 (radians)
        Returns:
        2-element array of coordinates in this system (radians)
      • toFK5

        public abstract double[] toFK5​(double c1,
                                       double c2,
                                       double epoch)
        Converts to FK5 J2000.0 from this system.
        Parameters:
        c1 - first coordinate in this system (radians)
        c2 - second coordinate in this system (radians)
        Returns:
        2-element array containing (RA, Dec) in FK5 (radians)
      • getName

        public java.lang.String getName()
        Returns the name of this system.
        Returns:
        system name
      • getDescription

        public java.lang.String getDescription()
        Returns a short description of this system.
        Returns:
        system description
      • getCoordinateUcds

        public java.lang.String[] getCoordinateUcds()
        Returns a suitable UCD1+ for each coordinate in this system.
        Returns:
        2-element array of coordinate UCDs
      • getCoordinateDescriptions

        public java.lang.String[] getCoordinateDescriptions()
        Returns a full description of each coordinate in this system.
        Returns:
        array of coordinate descriptions
      • getCoordinateNames

        public java.lang.String[] getCoordinateNames()
        Returns names of the coordinates in this system.
        Returns:
        array of coordinate names
      • getCoordinateColumnNames

        public java.lang.String[] getCoordinateColumnNames()
        Returns labels suitable for use as column names in this system.
        Returns:
        array of column names
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • getKnownSystems

        public static SkySystem[] getKnownSystems()
        Returns an array of all the systems known.
        Returns:
        system array
      • getSystemUsage

        public static java.lang.String getSystemUsage()
        Returns a snippet of XML which describes the systems and their meanings.
        Returns:
        XML description of this class and its instances
      • getSystemFor

        public static SkySystem getSystemFor​(java.lang.String sysName)
        Returns a system which matches a given string. Abbreviations may be used.
        Parameters:
        sysName - name to match
        Returns:
        a SkySystem, not null
        Throws:
        java.lang.IllegalArgumentException - if sysName isn't a system name