Package uk.ac.starlink.ttools.func
Class CoordsRadians
- java.lang.Object
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- uk.ac.starlink.ttools.func.CoordsRadians
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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)
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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.
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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.
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Field Detail
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DEGREE_RADIANS
public static final double DEGREE_RADIANS
The size of one degree in radians.- See Also:
- Constant Field Values
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HOUR_RADIANS
public static final double HOUR_RADIANS
The size of one hour of right ascension in radians.- See Also:
- Constant Field Values
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ARC_MINUTE_RADIANS
public static final double ARC_MINUTE_RADIANS
The size of one arcminute in radians.- See Also:
- Constant Field Values
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ARC_SECOND_RADIANS
public static final double ARC_SECOND_RADIANS
The size of one arcsecond in radians.- See Also:
- Constant Field Values
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Method Detail
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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
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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 radianssecFig
- number of decimal places in the seconds field- Returns:
- DMS-format string representing
rad
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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
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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 radianssecFig
- number of decimal places in the seconds field- Returns:
- HMS-format string representing
rad
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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, charactersdm[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
- ifdms
can't be parsed as a degrees:minutes:seconds string
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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, charactershm[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
- ifdms
can't be parsed as an hours:minutes:seconds string
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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 themin
orsec
arguments to be negative.- Parameters:
deg
- degrees part of anglemin
- minutes part of anglesec
- seconds part of angle- Returns:
- specified angle in radians
- Throws:
java.lang.IllegalArgumentException
- if an argument after the first non-zero one is negative
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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 anglemin
- minutes part of anglesec
- seconds part of angle- Returns:
- specified angle in radians
- Throws:
java.lang.IllegalArgumentException
- if an argument after the first non-zero one is negative
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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 radiansdec1
- declination of point 1 in radiansra2
- right ascension of point 2 in radiansdec2
- declination of point 2 in radians- Returns:
- angular distance between point 1 and point 2 in radians
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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 radiansdec1
- declination of point 1 in radiansra2
- right ascension of point 2 in radiansdec2
- declination of point 2 in radians- Returns:
- bearing in radians of point 2 from point 1
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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 radiansdec1
- declination of point1 in radiansradius1
- distance from origin of point1ra2
- right ascension of point 2 in radiansdec2
- declination of point2 in radiansradius2
- distance from origin of point2- Returns:
- the linear distance between point1 and point2;
units are as for
radius1
andradius2
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hoursToRadians
public static double hoursToRadians(double hours)
Converts hours to radians.- Parameters:
hours
- angle in hours- Returns:
- angle in radians
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degreesToRadians
public static double degreesToRadians(double deg)
Converts degrees to radians.- Parameters:
deg
- angle in degrees- Returns:
- angle in radians
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radiansToDegrees
public static double radiansToDegrees(double rad)
Converts radians to degrees.- Parameters:
rad
- angle in radians- Returns:
- angle in degrees
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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)
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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)
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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)
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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)
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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. Thebepoch
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)
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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. Thebepoch
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)
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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)
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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)
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