Package uk.ac.starlink.ttools.func

Class CoordsRadians

  • public class CoordsRadians
extends java.lang.Object
    Functions for angle transformations and manipulations, based on radians rather than degrees. In particular, methods for translating between radians and HH:MM:SS.S or DDD:MM:SS.S type sexagesimal representations are provided.
    Since:
    30 Apr 2004
    Author:
    Mark Taylor (Starlink)

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static double ARC_MINUTE_RADIANS
      The size of one arcminute in radians.
      static double ARC_SECOND_RADIANS
      The size of one arcsecond in radians.
      static double DEGREE_RADIANS
      The size of one degree in radians.
      static double HOUR_RADIANS
      The size of one hour of right ascension in radians.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static double decFK4toFK5radians​(double raFK4, double decFK4)
      Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Declination This assumes zero proper motion in the FK5 frame.
      static double decFK4toFK5Radians​(double raFK4, double decFK4, double bepoch)
      Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Declination.
      static double decFK5toFK4radians​(double raFK5, double decFK5)
      Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination.
      static double decFK5toFK4Radians​(double raFK5, double decFK5, double bepoch)
      Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination.
      static double degreesToRadians​(double deg)
      Converts degrees to radians.
      static double dmsToRadians​(double deg, double min, double sec)
      Converts degrees, minutes, seconds to an angle in radians.
      static double dmsToRadians​(java.lang.String dms)
      Converts a formatted degrees:minutes:seconds string to an angle in radians.
      static double hmsToRadians​(double hour, double min, double sec)
      Converts hours, minutes, seconds to an angle in radians.
      static double hmsToRadians​(java.lang.String hms)
      Converts a formatted hours:minutes:seconds string to an angle in radians.
      static double hoursToRadians​(double hours)
      Converts hours to radians.
      static double polarDistanceRadians​(double ra1, double dec1, double radius1, double ra2, double dec2, double radius2)
      Calculates the distance in three dimensional space between two points specified in spherical polar coordinates.
      static double posAngRadians​(double ra1, double dec1, double ra2, double dec2)
      Calculates the position angle between two points on the sky in radians.
      static double radiansToDegrees​(double rad)
      Converts radians to degrees.
      static java.lang.String radiansToDms​(double rad)
      Converts an angle in radians to a formatted degrees:minutes:seconds string.
      static java.lang.String radiansToDms​(double rad, int secFig)
      Converts an angle in radians to a formatted degrees:minutes:seconds string with a given number of decimal places in the seconds field.
      static java.lang.String radiansToHms​(double rad)
      Converts an angle in radians to a formatted hours:minutes:seconds string.
      static java.lang.String radiansToHms​(double rad, int secFig)
      Converts an angle in radians to a formatted hours:minutes:seconds string with a given number of decimal places in the seconds field.
      static double raFK4toFK5radians​(double raFK4, double decFK4)
      Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Right Ascension.
      static double raFK4toFK5Radians​(double raFK4, double decFK4, double bepoch)
      Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Right Ascension.
      static double raFK5toFK4radians​(double raFK5, double decFK5)
      Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination.
      static double raFK5toFK4Radians​(double raFK5, double decFK5, double bepoch)
      Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination.
      static double skyDistanceRadians​(double ra1, double dec1, double ra2, double dec2)
      Calculates the separation (distance around a great circle) of two points on the sky in radians.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • DEGREE_RADIANS

        public static final double DEGREE_RADIANS
        The size of one degree in radians.
        See Also:
        Constant Field Values

      • HOUR_RADIANS

        public static final double HOUR_RADIANS
        The size of one hour of right ascension in radians.
        See Also:
        Constant Field Values

      • ARC_MINUTE_RADIANS

        public static final double ARC_MINUTE_RADIANS
        The size of one arcminute in radians.
        See Also:
        Constant Field Values

      • ARC_SECOND_RADIANS

        public static final double ARC_SECOND_RADIANS
        The size of one arcsecond in radians.
        See Also:
        Constant Field Values

    • Method Detail

      • radiansToDms

        public static java.lang.String radiansToDms​(double rad)
        Converts an angle in radians to a formatted degrees:minutes:seconds string. No fractional part of the seconds field is given.
        Parameters:
        rad - angle in radians
        Returns:
        DMS-format string representing rad

      • radiansToDms

        public static java.lang.String radiansToDms​(double rad,
                                            int secFig)
        Converts an angle in radians to a formatted degrees:minutes:seconds string with a given number of decimal places in the seconds field.
        Parameters:
        rad - angle in radians
        secFig - number of decimal places in the seconds field
        Returns:
        DMS-format string representing rad

      • radiansToHms

        public static java.lang.String radiansToHms​(double rad)
        Converts an angle in radians to a formatted hours:minutes:seconds string. No fractional part of the seconds field is given.
        Parameters:
        rad - angle in radians
        Returns:
        HMS-format string representing rad

      • radiansToHms

        public static java.lang.String radiansToHms​(double rad,
                                            int secFig)
        Converts an angle in radians to a formatted hours:minutes:seconds string with a given number of decimal places in the seconds field.
        Parameters:
        rad - angle in radians
        secFig - number of decimal places in the seconds field
        Returns:
        HMS-format string representing rad

      • dmsToRadians

        public static double dmsToRadians​(java.lang.String dms)
        Converts a formatted degrees:minutes:seconds string to an angle in radians. Delimiters may be colon, space, characters dm[s], or some others. Additional spaces and leading +/- are permitted. The :seconds part is optional.
        Parameters:
        dms - formatted DMS string
        Returns:
        angle in radians specified by dms
        Throws:
        java.lang.NumberFormatException - if dms can't be parsed as a degrees:minutes:seconds string

      • hmsToRadians

        public static double hmsToRadians​(java.lang.String hms)
        Converts a formatted hours:minutes:seconds string to an angle in radians. Delimiters may be colon, space, characters hm[s], or some others. Additional spaces and leading +/- are permitted. The :seconds part is optional.
        Parameters:
        hms - formatted HMS string
        Returns:
        angle in radians specified by hms
        Throws:
        java.lang.NumberFormatException - if dms can't be parsed as an hours:minutes:seconds string

      • dmsToRadians

        public static double dmsToRadians​(double deg,
                                  double min,
                                  double sec)
        Converts degrees, minutes, seconds to an angle in radians.

        In conversions of this type, one has to be careful to get the sign right in converting angles which are between 0 and -1 degrees. This routine uses the sign bit of the deg argument, taking care to distinguish between +0 and -0 (their internal representations are different for floating point values). It is illegal for the min or sec arguments to be negative.

        Parameters:
        deg - degrees part of angle
        min - minutes part of angle
        sec - seconds part of angle
        Returns:
        specified angle in radians
        Throws:
        java.lang.IllegalArgumentException - if an argument after the first non-zero one is negative

      • hmsToRadians

        public static double hmsToRadians​(double hour,
                                  double min,
                                  double sec)
        Converts hours, minutes, seconds to an angle in radians.

        In conversions of this type, one has to be careful to get the sign right in converting angles which are between 0 and -1 hours. This routine uses the sign bit of the hour argument, taking care to distinguish between +0 and -0 (their internal representations are different for floating point values).

        Parameters:
        hour - degrees part of angle
        min - minutes part of angle
        sec - seconds part of angle
        Returns:
        specified angle in radians
        Throws:
        java.lang.IllegalArgumentException - if an argument after the first non-zero one is negative

      • skyDistanceRadians

        public static double skyDistanceRadians​(double ra1,
                                        double dec1,
                                        double ra2,
                                        double dec2)
        Calculates the separation (distance around a great circle) of two points on the sky in radians.
        Parameters:
        ra1 - right ascension of point 1 in radians
        dec1 - declination of point 1 in radians
        ra2 - right ascension of point 2 in radians
        dec2 - declination of point 2 in radians
        Returns:
        angular distance between point 1 and point 2 in radians

      • posAngRadians

        public static double posAngRadians​(double ra1,
                                   double dec1,
                                   double ra2,
                                   double dec2)
        Calculates the position angle between two points on the sky in radians. The result is in the range +/-pi. If point 2 is due east of point 1, the result is +pi/2. Zero is returned if the points are coincident.
        Parameters:
        ra1 - right ascension of point 1 in radians
        dec1 - declination of point 1 in radians
        ra2 - right ascension of point 2 in radians
        dec2 - declination of point 2 in radians
        Returns:
        bearing in radians of point 2 from point 1

      • polarDistanceRadians

        public static double polarDistanceRadians​(double ra1,
                                          double dec1,
                                          double radius1,
                                          double ra2,
                                          double dec2,
                                          double radius2)
        Calculates the distance in three dimensional space between two points specified in spherical polar coordinates.
        Parameters:
        ra1 - right ascension of point 1 in radians
        dec1 - declination of point1 in radians
        radius1 - distance from origin of point1
        ra2 - right ascension of point 2 in radians
        dec2 - declination of point2 in radians
        radius2 - distance from origin of point2
        Returns:
        the linear distance between point1 and point2; units are as for radius1 and radius2

      • hoursToRadians

        public static double hoursToRadians​(double hours)
        Converts hours to radians.
        Parameters:
        hours - angle in hours
        Returns:
        angle in radians

      • degreesToRadians

        public static double degreesToRadians​(double deg)
        Converts degrees to radians.
        Parameters:
        deg - angle in degrees
        Returns:
        angle in radians

      • radiansToDegrees

        public static double radiansToDegrees​(double rad)
        Converts radians to degrees.
        Parameters:
        rad - angle in radians
        Returns:
        angle in degrees

      • raFK4toFK5radians

        public static double raFK4toFK5radians​(double raFK4,
                                       double decFK4)
        Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Right Ascension. This assumes zero proper motion in the FK5 frame.
        Parameters:
        raFK4 - right ascension in B1950.0 FK4 system (radians)
        decFK4 - declination in B1950.0 FK4 system (radians)
        Returns:
        right ascension in J2000.0 FK5 system (radians)
        See Also:
        Pal.Fk45z(uk.ac.starlink.pal.AngleDR, double)

      • decFK4toFK5radians

        public static double decFK4toFK5radians​(double raFK4,
                                        double decFK4)
        Converts a B1950.0 FK4 position to J2000.0 FK5 at an epoch of B1950.0 yielding Declination This assumes zero proper motion in the FK5 frame.
        Parameters:
        raFK4 - right ascension in B1950.0 FK4 system (radians)
        decFK4 - declination in B1950.0 FK4 system (radians)
        Returns:
        declination in J2000.0 FK5 system (radians)
        See Also:
        Pal.Fk45z(uk.ac.starlink.pal.AngleDR, double)

      • raFK5toFK4radians

        public static double raFK5toFK4radians​(double raFK5,
                                       double decFK5)
        Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.
        Parameters:
        raFK5 - right ascension in J2000.0 FK5 system (radians)
        decFK5 - declination in J2000.0 FK5 system (radians)
        Returns:
        right ascension in the FK4 system (radians)
        See Also:
        Pal.Fk54z(uk.ac.starlink.pal.AngleDR, double)

      • decFK5toFK4radians

        public static double decFK5toFK4radians​(double raFK5,
                                        double decFK5)
        Converts a J2000.0 FK5 position to B1950.0 FK4 at an epoch of B1950.0 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.
        Parameters:
        raFK5 - right ascension in J2000.0 FK5 system (radians)
        decFK5 - declination in J2000.0 FK5 system (radians)
        Returns:
        right ascension in the FK4 system (radians)
        See Also:
        Pal.Fk54z(uk.ac.starlink.pal.AngleDR, double)

      • raFK4toFK5Radians

        public static double raFK4toFK5Radians​(double raFK4,
                                       double decFK4,
                                       double bepoch)
        Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Right Ascension. This assumes zero proper motion in the FK5 frame. The bepoch parameter is the epoch at which the position in the FK4 frame was determined.
        Parameters:
        raFK4 - right ascension in B1950.0 FK4 system (radians)
        decFK4 - declination in B1950.0 FK4 system (radians)
        bepoch - Besselian epoch
        Returns:
        right ascension in J2000.0 FK5 system (radians)
        See Also:
        Pal.Fk45z(uk.ac.starlink.pal.AngleDR, double)

      • decFK4toFK5Radians

        public static double decFK4toFK5Radians​(double raFK4,
                                        double decFK4,
                                        double bepoch)
        Converts a B1950.0 FK4 position to J2000.0 FK5 yielding Declination. This assumes zero proper motion in the FK5 frame. The bepoch parameter is the epoch at which the position in the FK4 frame was determined.
        Parameters:
        raFK4 - right ascension in B1950.0 FK4 system (radians)
        decFK4 - declination in B1950.0 FK4 system (radians)
        bepoch - Besselian epoch
        Returns:
        declination in J2000.0 FK5 system (radians)
        See Also:
        Pal.Fk45z(uk.ac.starlink.pal.AngleDR, double)

      • raFK5toFK4Radians

        public static double raFK5toFK4Radians​(double raFK5,
                                       double decFK5,
                                       double bepoch)
        Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.
        Parameters:
        raFK5 - right ascension in J2000.0 FK5 system (radians)
        decFK5 - declination in J2000.0 FK5 system (radians)
        bepoch - Besselian epoch
        Returns:
        right ascension in the FK4 system (radians)
        See Also:
        Pal.Fk54z(uk.ac.starlink.pal.AngleDR, double)

      • decFK5toFK4Radians

        public static double decFK5toFK4Radians​(double raFK5,
                                        double decFK5,
                                        double bepoch)
        Converts a J2000.0 FK5 position to B1950.0 FK4 yielding Declination. This assumes zero proper motion, parallax and radial velocity in the FK5 frame.
        Parameters:
        raFK5 - right ascension in J2000.0 FK5 system (radians)
        decFK5 - declination in J2000.0 FK5 system (radians)
        bepoch - Besselian epoch
        Returns:
        right ascension in the FK4 system (radians)
        See Also:
        Pal.Fk54z(uk.ac.starlink.pal.AngleDR, double)