JASTRONOMY::J2000 Struct Reference

Conversion of source location. More...

#include <JAstronomy.hh>

Public Types
enum	CONVERSION { FROM = -1 , TO = +1 }
	Conversion options. More...

Static Public Member Functions
static angle_type_rad	convert (const double t1_s, const angle_type_rad &location, const J2000::CONVERSION option)
	Convert source location according J2000 at given time.

Detailed Description

Conversion of source location.

Definition at line 375 of file JAstronomy.hh.

Member Enumeration Documentation

CONVERSION

enum JASTRONOMY::J2000::CONVERSION

Conversion options.

Enumerator
FROM
TO

Definition at line 379 of file JAstronomy.hh.

                    {
      FROM = -1,
      TO   = +1
    };

Member Function Documentation

convert()

static angle_type_rad JASTRONOMY::J2000::convert ( const double t1_s, const angle_type_rad & location, const J2000::CONVERSION option )

inlinestatic

Convert source location according J2000 at given time.

Adapted from aanet/astro/Astro.cc

Parameters

t1_s	time since MJD [s]
location	source location
option	option

Returns

source location

Definition at line 394 of file JAstronomy.hh.

    {
      using namespace JPP;
 
      // --- get the rotation matrix ----
      // NOTE: (from seatray Astro): Julian epoch of J2000 time definition is 2000,
      // corresponding by definition to 2451545.0 TT (unmodified) Julian date!
 
      double mjd   = t1_s / NUMBER_OF_SECONDS_PER_DAY;   // [days]
      double epoch = 2000;
      double R[3][3] {};
 
      slaPrenut(epoch, mjd, R);                        // SLALIB function to get the matrix of precession and nutation
 
      JMatrix3D  M  = JMatrix3D(R[0][0], R[0][1], R[0][2],
                                R[1][0], R[1][1], R[1][2],
                                R[2][0], R[2][1], R[2][2]);
 
      M.transpose();                                     // transpose 'cause of fortan matrix convention 
 
      if (option == J2000::TO) {
 
        JSVD3D V(M);
 
        M = V.invert();
      }
 
      // convert (declination, right ascension) to polar coordinates (theta, phi)
 
      JDirection3D v(JAngle3D(PI/2 - location._theta_, location._phi_));
 
      // apply transformation
      
      v.transform(M);
 
      // convert polar coordinates (theta, phi) to (declination, right ascension)
 
      return angle_type_rad(PI/2 - v.getTheta(), v.getPhi());
    }

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The documentation for this struct was generated from the following file:

• JAstronomy.hh