lsst::afw::coord::Fk5Coord Class Reference

A class to handle Fk5 coordinates (inherits from Coord) More...

#include <Coord.h>

Inheritance diagram for lsst::afw::coord::Fk5Coord:

Public Types
typedef boost::shared_ptr < Fk5Coord >	Ptr
Public Types inherited from lsst::afw::coord::Coord
typedef boost::shared_ptr< Coord >	Ptr
typedef boost::shared_ptr < Coord const >	ConstPtr

Public Member Functions
	Fk5Coord (lsst::afw::geom::Point2D const &p2d, lsst::afw::geom::AngleUnit unit=lsst::afw::geom::degrees, double const epoch=2000.0)
	Fk5Coord (lsst::afw::geom::Point3D const &p3d, double const epoch=2000.0, bool normalize=true, lsst::afw::geom::Angle const defaultLongitude=lsst::afw::geom::Angle(0.))
	Fk5Coord (lsst::afw::geom::Angle const ra, lsst::afw::geom::Angle const dec, double const epoch=2000.0)
	Fk5Coord (std::string const ra, std::string const dec, double const epoch=2000.0)
	Fk5Coord ()
virtual Coord::Ptr	clone () const
virtual std::string	getClassName () const
Fk5Coord	precess (double const epochTo) const
	Precess ourselves from whence we are to a new epoch. More...
lsst::afw::geom::Angle	getRa () const
lsst::afw::geom::Angle	getDec () const
std::string	getRaStr (lsst::afw::geom::AngleUnit unit) const
std::string	getDecStr () const
virtual Fk5Coord	toFk5 (double const epoch) const
	Convert ourself to Fk5 (ie. a no-op): RA, Dec (precess to new epoch) More...
virtual Fk5Coord	toFk5 () const
	Convert ourself to Fk5 (ie. a no-op): RA, Dec (keep current epoch) More...
virtual IcrsCoord	toIcrs () const
	Convert ourself to ICRS: RA, Dec (basically J2000) More...
virtual GalacticCoord	toGalactic () const
	Convert ourself to Galactic: l, b. More...
virtual EclipticCoord	toEcliptic (double const epoch) const
	Convert ourself to Ecliptic: lambda, beta (precess to new epoch) More...
virtual EclipticCoord	toEcliptic () const
	Convert ourself to Ecliptic: lambda, beta (use current epoch) More...
virtual TopocentricCoord	toTopocentric (Observatory const &obs, lsst::daf::base::DateTime const &obsDate) const
	Convert ourself to Altitude/Azimuth: alt, az. More...
Public Member Functions inherited from lsst::afw::coord::Coord
	Coord (lsst::afw::geom::Point2D const &p2d, lsst::afw::geom::AngleUnit unit=lsst::afw::geom::degrees, double const epoch=2000.0)
	Constructor for the Coord base class. More...
	Coord (lsst::afw::geom::Point3D const &p3d, double const epoch=2000.0, bool normalize=true, lsst::afw::geom::Angle const defaultLongitude=lsst::afw::geom::Angle(0.))
	Constructor for the Coord base class. More...
	Coord (lsst::afw::geom::Angle const ra, lsst::afw::geom::Angle const dec, double const epoch=2000.0)
	Constructor for the Coord base class. More...
	Coord (std::string const ra, std::string const dec, double const epoch=2000.0)
	Constructor for the Coord base class. More...
	Coord ()
	Default constructor for the Coord base class. More...
virtual	~Coord ()
virtual void	reset (lsst::afw::geom::Angle const longitude, lsst::afw::geom::Angle const latitude)
virtual void	reset (lsst::afw::geom::Angle const longitude, lsst::afw::geom::Angle const latitude, double const epoch)
	Reset our coordinates wholesale. More...
double	getEpoch () const
lsst::afw::geom::Point2D	getPosition (lsst::afw::geom::AngleUnit unit=lsst::afw::geom::degrees) const
	Return our contents in a Point2D object. More...
lsst::afw::geom::Point3D	getVector () const
	Return our contents in a position vector. More...
virtual std::pair< std::string, std::string >	getCoordNames () const
lsst::afw::geom::Angle	operator[] (int const index) const
	Provide access to our contents via an index. More...
bool	operator== (Coord const &rhs) const
	Equality operator, compares each element directly. More...
lsst::afw::geom::Angle	getLongitude () const
	The main access method for the longitudinal coordinate. More...
lsst::afw::geom::Angle	getLatitude () const
	The main access method for the latitudinal coordinate. More...
std::string	getLongitudeStr (lsst::afw::geom::AngleUnit unit) const
	Allow quick access to the longitudinal coordinate as a string. More...
std::string	getLatitudeStr () const
	Allow quick access to the longitude coordinate as a string. More...
Coord	transform (Coord const &poleFrom, Coord const &poleTo) const
	Tranform our current coords to another spherical polar system. More...
lsst::afw::geom::Angle	angularSeparation (Coord const &c) const
	compute the angular separation between two Coords More...
std::pair < lsst::afw::geom::Angle, lsst::afw::geom::Angle >	getOffsetFrom (Coord const &c) const
	Compute the offset from a coordinate. More...
std::pair < lsst::afw::geom::Angle, lsst::afw::geom::Angle >	getTangentPlaneOffset (Coord const &c) const
	Get the offset on the tangent plane. More...
void	rotate (Coord const &axis, lsst::afw::geom::Angle const theta)
	Rotate our current coords about a pole. More...
lsst::afw::geom::Angle	offset (lsst::afw::geom::Angle const phi, lsst::afw::geom::Angle const arcLen)
	offset our current coords along a great circle defined by an angle wrt a declination parallel More...
Coord::Ptr	convert (CoordSystem system) const
	Convert to a specified Coord type. More...

Detailed Description

A class to handle Fk5 coordinates (inherits from Coord)

Definition at line 191 of file Coord.h.

Member Typedef Documentation

typedef boost::shared_ptr<Fk5Coord> lsst::afw::coord::Fk5Coord::Ptr

Definition at line 194 of file Coord.h.

Constructor & Destructor Documentation

lsst::afw::coord::Fk5Coord::Fk5Coord ( lsst::afw::geom::Point2D const &  p2d, lsst::afw::geom::AngleUnit  unit = lsst::afw::geom::degrees, double const  epoch = 2000.0  )

inline

Definition at line 196 of file Coord.h.

                                                                                                                         :
        Coord(p2d, unit, epoch) {}

lsst::afw::coord::Fk5Coord::Fk5Coord ( lsst::afw::geom::Point3D const &  p3d, double const  epoch = 2000.0, bool  normalize = true, lsst::afw::geom::Angle const  defaultLongitude = lsst::afw::geom::Angle(0.)  )

inline

Definition at line 198 of file Coord.h.

                                                                            :
        Coord(p3d, epoch, normalize, defaultLongitude) {}

lsst::afw::coord::Fk5Coord::Fk5Coord ( lsst::afw::geom::Angle const  ra, lsst::afw::geom::Angle const  dec, double const  epoch = 2000.0  )

inline

Definition at line 202 of file Coord.h.

                                                                                                 : 
        Coord(ra, dec, epoch) {}

lsst::afw::coord::Fk5Coord::Fk5Coord ( std::string const  ra, std::string const  dec, double const  epoch = 2000.0  )

inline

Definition at line 204 of file Coord.h.

                                                                                   :
        Coord(ra, dec, epoch) {}

lsst::afw::coord::Fk5Coord::Fk5Coord ( )

inline

Definition at line 206 of file Coord.h.

: Coord() {}

Member Function Documentation

virtual Coord::Ptr lsst::afw::coord::Fk5Coord::clone ( ) const

inlinevirtual

Reimplemented from lsst::afw::coord::Coord.

Definition at line 208 of file Coord.h.

{ return Fk5Coord::Ptr(new Fk5Coord(*this)); }

virtual std::string lsst::afw::coord::Fk5Coord::getClassName ( ) const

inlinevirtual

Reimplemented from lsst::afw::coord::Coord.

Definition at line 210 of file Coord.h.

{ return "Fk5Coord"; }

lsst::afw::geom::Angle lsst::afw::coord::Fk5Coord::getDec ( ) const

inline

Definition at line 215 of file Coord.h.

{ return getLatitude(); }    

std::string lsst::afw::coord::Fk5Coord::getDecStr ( ) const

inline

Definition at line 217 of file Coord.h.

{ return getLatitudeStr(); }     

lsst::afw::geom::Angle lsst::afw::coord::Fk5Coord::getRa ( ) const

inline

Definition at line 214 of file Coord.h.

{ return getLongitude(); }   

std::string lsst::afw::coord::Fk5Coord::getRaStr ( lsst::afw::geom::AngleUnit  unit ) const

inline

Definition at line 216 of file Coord.h.

{ return getLongitudeStr(unit); }

afwCoord::Fk5Coord lsst::afw::coord::Fk5Coord::precess

(

double const

epochTo

)

const

Precess ourselves from whence we are to a new epoch.

Parameters

epochTo

epoch to precess to

Definition at line 947 of file Coord.cc.

                                                      {

    // return a copy if the epochs are the same
    if ( fabs(getEpoch() - epochTo) < epochTolerance) {
        return Fk5Coord(getLongitude(), getLatitude(), getEpoch());
    }
    
    dafBase::DateTime const dateFrom(getEpoch(), dafBase::DateTime::EPOCH, dafBase::DateTime::TAI);
    dafBase::DateTime const dateTo(epochTo, dafBase::DateTime::EPOCH, dafBase::DateTime::TAI);
    double const jd0 = dateFrom.get(dafBase::DateTime::JD);
    double const jd  = dateTo.get(dafBase::DateTime::JD);

    double const T   = (jd0 - JD2000)/36525.0;
    double const t   = (jd - jd0)/36525.0;
    double const tt  = t*t;
    double const ttt = tt*t;

    afwGeom::Angle const xi    = ((2306.2181 + 1.39656*T - 0.000139*T*T)*t +
                                  (0.30188 - 0.000344*T)*tt + 0.017998*ttt) * afwGeom::arcseconds;
    afwGeom::Angle const z     = ((2306.2181 + 1.39656*T - 0.000139*T*T)*t +
                                  (1.09468 + 0.000066*T)*tt + 0.018203*ttt) * afwGeom::arcseconds;
    afwGeom::Angle const theta = ((2004.3109 - 0.85330*T - 0.000217*T*T)*t -
                                  (0.42665 + 0.000217*T)*tt - 0.041833*ttt) * afwGeom::arcseconds;

    Fk5Coord fk5 = this->toFk5();
    afwGeom::Angle const alpha0 = fk5.getRa();
    afwGeom::Angle const delta0 = fk5.getDec();
    
    double const a = std::cos(delta0) * std::sin((alpha0 + xi));
    double const b = std::cos(theta)  * std::cos(delta0) * std::cos((alpha0 + xi)) - std::sin(theta) * std::sin(delta0);
    double const c = std::sin(theta)  * std::cos(delta0) * std::cos((alpha0 + xi)) + std::cos(theta) * std::sin(delta0);

    afwGeom::Angle const alpha = (std::atan2(a,b) + z) * afwGeom::radians;
    afwGeom::Angle const delta = std::asin(c) * afwGeom::radians;
    
    return Fk5Coord(alpha, delta, epochTo);
}

afwCoord::EclipticCoord lsst::afw::coord::Fk5Coord::toEcliptic ( double const  epoch ) const

virtual

Convert ourself to Ecliptic: lambda, beta (precess to new epoch)

Reimplemented from lsst::afw::coord::Coord.

Definition at line 886 of file Coord.cc.

                                                                           {
    afwGeom::Angle const eclPoleIncl = eclipticPoleInclination(epoch);
    Coord const eclPoleInEquatorial(270.0 * afwGeom::degrees, (90.0 * afwGeom::degrees) - eclPoleIncl, epoch);
    Coord const equPoleInEcliptic(90.0 * afwGeom::degrees, (90.0 * afwGeom::degrees) - eclPoleIncl, epoch);
    Coord c = transform(equPoleInEcliptic, eclPoleInEquatorial); 
    return EclipticCoord(c.getLongitude(), c.getLatitude(), epoch);
}

afwCoord::EclipticCoord lsst::afw::coord::Fk5Coord::toEcliptic ( ) const

virtual

Convert ourself to Ecliptic: lambda, beta (use current epoch)

Reimplemented from lsst::afw::coord::Coord.

Definition at line 896 of file Coord.cc.

                                                         {
    return this->toEcliptic(getEpoch());
}

afwCoord::Fk5Coord lsst::afw::coord::Fk5Coord::toFk5 ( double const  epoch ) const

virtual

Convert ourself to Fk5 (ie. a no-op): RA, Dec (precess to new epoch)

Reimplemented from lsst::afw::coord::Coord.

Definition at line 839 of file Coord.cc.

                                                                 {
    return Fk5Coord(getLongitude(), getLatitude(), getEpoch()).precess(epoch);
}

afwCoord::Fk5Coord lsst::afw::coord::Fk5Coord::toFk5 ( ) const

virtual

Convert ourself to Fk5 (ie. a no-op): RA, Dec (keep current epoch)

Reimplemented from lsst::afw::coord::Coord.

Definition at line 845 of file Coord.cc.

                                               {
    return Fk5Coord(getLongitude(), getLatitude(), getEpoch());
}

afwCoord::GalacticCoord lsst::afw::coord::Fk5Coord::toGalactic ( ) const

virtual

Convert ourself to Galactic: l, b.

Reimplemented from lsst::afw::coord::Coord.

Definition at line 868 of file Coord.cc.

                                                         {

    // if we're epoch==2000, we can transform, otherwise we need to precess first
    Fk5Coord c;
    if ( fabs(getEpoch() - 2000.0) > epochTolerance ) {
        c = precess(2000.0);
    } else {
        c = *this;
    }
    
    Coord ct = c.transform(Fk5PoleInGalactic(), GalacticPoleInFk5());
    return GalacticCoord(ct.getLongitude(), ct.getLatitude());
    
}

afwCoord::IcrsCoord lsst::afw::coord::Fk5Coord::toIcrs ( ) const

virtual

Convert ourself to ICRS: RA, Dec (basically J2000)

Reimplemented from lsst::afw::coord::Coord.

Definition at line 853 of file Coord.cc.

                                                 {

    // only do the precession to 2000 if we're not already there.
    if ( fabs(getEpoch() - 2000.0) > epochTolerance ) {
        afwCoord::Fk5Coord c = precess(2000.0);
        return IcrsCoord(c.getLongitude(), c.getLatitude());
    } else {
        return IcrsCoord(getLongitude(), getLatitude());
    }
}

afwCoord::TopocentricCoord lsst::afw::coord::Fk5Coord::toTopocentric ( Observatory const &  obs, lsst::daf::base::DateTime const &  obsDate  ) const

virtual

Convert ourself to Altitude/Azimuth: alt, az.

Parameters

obs	observatory
obsDate	date of obs.

Reimplemented from lsst::afw::coord::Coord.

Definition at line 903 of file Coord.cc.

                                                                    {

    // make sure we precess to the epoch
    Fk5Coord fk5 = precess(obsDate.get(dafBase::DateTime::EPOCH));

    // greenwich sidereal time
    afwGeom::Angle theta0 = meanSiderealTimeGreenwich(obsDate.get(dafBase::DateTime::JD));
    theta0.wrap();

    // lat/long of the observatory
    afwGeom::Angle const phi             = obs.getLatitude();
    afwGeom::Angle const L               = obs.getLongitude();

    // ra/dec of the target
    afwGeom::Angle const alpha           = fk5.getRa();
    afwGeom::Angle const delta           = fk5.getDec();
                               
    afwGeom::Angle const H               = theta0 + L - alpha;

    // compute the altitude, h
    double const sinh            = std::sin(phi)* std::sin(delta) + std::cos(phi) * std::cos(delta) * std::cos(H);
    afwGeom::Angle const h               = std::asin(sinh) * afwGeom::radians;

    // compute the azimuth, A
    double const tanAnumerator   = std::sin(H);
    double const tanAdenominator = (std::cos(H) * std::sin(phi) - std::tan(delta) * std::cos(phi));
    
    // Equations used here assume azimuth is with respect to South
    // but we use the North as our origin ... must add 180 deg
    afwGeom::Angle A = (180.0*afwGeom::degrees) + atan2(tanAnumerator, tanAdenominator)* afwGeom::radians;
    A.wrap();
    
    return TopocentricCoord(A, h, obsDate.get(dafBase::DateTime::EPOCH), obs);
}

---

The documentation for this class was generated from the following files:

• /home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/coord/Coord.h
• /home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/src/coord/Coord.cc