GSkyDir.cpp
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/***************************************************************************
* GSkyDir.cpp - Class that implements a sky direction *
* ----------------------------------------------------------------------- *
* copyright : (C) 2008 by Jurgen Knodlseder *
* ----------------------------------------------------------------------- *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* ----------------------------------------------------------------------- *
***************************************************************************/
/* __ Includes ___________________________________________________________ */
#include <cmath>
#include "GException.hpp"
#include "GTools.hpp"
#include "GSkyDir.hpp"
/* __ Namespaces _________________________________________________________ */
/* __ Method name definitions ____________________________________________ */
/* __ Macros _____________________________________________________________ */
/* __ Coding definitions _________________________________________________ */
/* __ Debug definitions __________________________________________________ */
/* __ Prototype __________________________________________________________ */
void euler(const int& type, const double& xin, const double &yin,
double* xout, double *yout);
/*==========================================================================
= =
= GSkyDir constructors/destructors =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Constructor
***************************************************************************/
GSkyDir::GSkyDir()
{
// Initialise class members for clean destruction
init_members();
// Return
return;
}
/***********************************************************************//**
* @brief Copy constructor
*
* @param[in] dir Sky direction from which class should be instantiated.
***************************************************************************/
GSkyDir::GSkyDir(const GSkyDir& dir)
{
// Initialise class members for clean destruction
init_members();
// Copy members
copy_members(dir);
// Return
return;
}
/***********************************************************************//**
* @brief Destructor
***************************************************************************/
GSkyDir::~GSkyDir()
{
// Free members
free_members();
// Return
return;
}
/*==========================================================================
= =
= GSkyDir operators =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Assignment operator
***************************************************************************/
GSkyDir& GSkyDir::operator= (const GSkyDir& dir)
{
// Execute only if object is not identical
if (this != &dir) {
// Free members
free_members();
// Initialise private members for clean destruction
init_members();
// Copy members
copy_members(dir);
} // endif: object was not identical
// Return this object
return *this;
}
/*==========================================================================
= =
= GSkyDir public methods =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Set equatorial sky direction (radians)
*
* @param[in] ra Right Ascension in radians.
* @param[in] dec Declination in radians.
***************************************************************************/
void GSkyDir::radec(const double& ra, const double& dec)
{
// Set attributes
m_has_lb = 0;
m_has_radec = 1;
// Set direction
m_ra = ra;
m_dec = dec;
// Return
return;
}
/***********************************************************************//**
* @brief Set equatorial sky direction (degrees)
*
* @param[in] ra Right Ascension in degrees.
* @param[in] dec Declination in degrees.
***************************************************************************/
void GSkyDir::radec_deg(const double& ra, const double& dec)
{
// Set attributes
m_has_lb = 0;
m_has_radec = 1;
// Set direction
m_ra = ra * deg2rad;
m_dec = dec * deg2rad;
// Return
return;
}
/***********************************************************************//**
* @brief Set galactic sky direction (radians)
*
* @param[in] l Galactic longitude in radians.
* @param[in] b Galactic latitude in radians.
***************************************************************************/
void GSkyDir::lb(const double& l, const double& b)
{
// Set attributes
m_has_lb = 1;
m_has_radec = 0;
// Set direction
m_l = l;
m_b = b;
// Return
return;
}
/***********************************************************************//**
* @brief Set galactic sky direction (degrees)
*
* @param[in] l Galactic longitude in degrees.
* @param[in] b Galactic latitude in degrees.
***************************************************************************/
void GSkyDir::lb_deg(const double& l, const double& b)
{
// Set attributes
m_has_lb = 1;
m_has_radec = 0;
// Set direction
m_l = l * deg2rad;
m_b = b * deg2rad;
// Return
return;
}
/***********************************************************************//**
* @brief Returns galactic longitude in radians
***************************************************************************/
double GSkyDir::l(void)
{
// If we have no galactic coordinates then get them now
if (!m_has_lb && m_has_radec)
equ2gal();
// Return galactic longitude
return m_l;
}
/***********************************************************************//**
* @brief Returns galactic longitude in degrees
***************************************************************************/
double GSkyDir::l_deg(void)
{
// If we have no galactic coordinates then get them now
if (!m_has_lb && m_has_radec)
equ2gal();
// Return galactic longitude
return m_l * rad2deg;
}
/***********************************************************************//**
* @brief Returns galactic latitude in radians
***************************************************************************/
double GSkyDir::b(void)
{
// If we have no galactic coordinates then get them now
if (!m_has_lb && m_has_radec)
equ2gal();
// Return galactic latitude
return m_b;
}
/***********************************************************************//**
* @brief Returns galactic latitude in degrees
***************************************************************************/
double GSkyDir::b_deg(void)
{
// If we have no galactic coordinates then get them now
if (!m_has_lb && m_has_radec)
equ2gal();
// Return galactic latitude
return m_b * rad2deg;
}
/***********************************************************************//**
* @brief Returns Right Ascension in radians
***************************************************************************/
double GSkyDir::ra(void)
{
// If we have no equatorial coordinates then get them now
if (!m_has_radec && m_has_lb)
gal2equ();
// Return Right Ascension
return m_ra;
}
/***********************************************************************//**
* @brief Returns Right Ascension in degrees
***************************************************************************/
double GSkyDir::ra_deg(void)
{
// If we have no equatorial coordinates then get them now
if (!m_has_radec && m_has_lb)
gal2equ();
// Return Right Ascension
return m_ra * rad2deg;
}
/***********************************************************************//**
* @brief Returns Declination in radians
***************************************************************************/
double GSkyDir::dec(void)
{
// If we have no equatorial coordinates then get them now
if (!m_has_radec && m_has_lb)
gal2equ();
// Return Declination
return m_dec;
}
/***********************************************************************//**
* @brief Returns Declination in degrees
***************************************************************************/
double GSkyDir::dec_deg(void)
{
// If we have no equatorial coordinates then get them now
if (!m_has_radec && m_has_lb)
gal2equ();
// Return Declination
return m_dec * rad2deg;
}
/*==========================================================================
= =
= GSkyDir private methods =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Initialise class members
***************************************************************************/
void GSkyDir::init_members(void)
{
// Initialise members
m_has_lb = 0;
m_has_radec = 0;
m_l = 0.0;
m_b = 0.0;
m_ra = 0.0;
m_dec = 0.0;
// Return
return;
}
/***********************************************************************//**
* @brief Copy class members
*
* @param[in] dir Sky direction from which members should be copied
***************************************************************************/
void GSkyDir::copy_members(const GSkyDir& dir)
{
// Copy attributes
m_has_lb = dir.m_has_lb;
m_has_radec = dir.m_has_radec;
m_l = dir.m_l;
m_b = dir.m_b;
m_ra = dir.m_ra;
m_dec = dir.m_dec;
// Return
return;
}
/***********************************************************************//**
* @brief Delete class members
***************************************************************************/
void GSkyDir::free_members(void)
{
// Free memory
// Signal free pointers
// Return
return;
}
/***********************************************************************//**
* @brief Convert equatorial to galactic coordinates
***************************************************************************/
void GSkyDir::equ2gal(void)
{
// Convert from equatorial to galactic
euler(0, m_ra, m_dec, &m_l, &m_b);
// Return
return;
}
/***********************************************************************//**
* @brief Convert galactic to equatorial coordinates
***************************************************************************/
void GSkyDir::gal2equ(void)
{
// Convert from galactic to equatorial
euler(1, m_l, m_b, &m_ra, &m_dec);
// Return
return;
}
/*==========================================================================
= =
= GSkyDir friends =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Output operator
*
* @param[in] os Output stream
* @param[in] column Sky direction to put in output stream
***************************************************************************/
ostream& operator<< (ostream& os, const GSkyDir& dir)
{
// Create coordinate system dependent output
if (dir.m_has_lb)
os << "(l,b)=(" << dir.m_l*rad2deg << "," << dir.m_b*rad2deg << ")";
else if (dir.m_has_radec)
os << "(RA,Dec)=(" << dir.m_ra*rad2deg << "," << dir.m_dec*rad2deg << ")";
// Return output stream
return os;
}
/*==========================================================================
= =
= Other functions used by GSkyDir =
= =
==========================================================================*/
/***********************************************************************//**
* @brief General coordinate transformation routine for J2000
*
* @param[in] type Conversion type (0=equ2gal, 1=gal2equ)
* @param[in] xin Input longitude (RA or GLON) in radians.
* @param[in] yin Input latitude (Dec or GLAT) in radians.
* @param[out] xout Output longitude in radians.
* @param[out] yout Output latitude in radians.
***************************************************************************/
void euler(const int& type, const double& xin, const double &yin,
double* xout, double *yout)
{
// Set transformation constants
const double psi[] = {0.57477043300, 4.9368292465};
const double stheta[] = {0.88998808748, -0.88998808748};
const double ctheta[] = {0.45598377618, 0.45598377618};
const double phi[] = {4.9368292465, 0.57477043300};
// Perform transformation
double a = xin - phi[type];
double b = yin;
double sb = sin(b);
double cb = cos(b);
double cbsa = cb * sin(a);
//
a = atan2(ctheta[type] * cbsa + stheta[type] * sb, cb * cos(a));
b = -stheta[type] * cbsa + ctheta[type] * sb;
if (b > 1.0)
b = 1.0;
//
*yout = asin(b);
*xout = modulo((a+psi[type] + fourpi), twopi);
// Return
return;
}