MeasData.h

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// # MeasData.h: MeasData provides Measure computing data
// # Copyright (C) 1995,1996,1997,1999,2003
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library is distributed in the hope that it will be useful, but WITHOUT
// # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef MEASURES_MEASDATA_H
#define MEASURES_MEASDATA_H
 
// # Includes
#include <casacore/casa/aips.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class RotMatrix;
 
// <summary>
// MeasData provides Measure computing data
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tMeasMath" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class=Measure>Measure</linkto> class
// </prerequisite>
//
// <etymology>
// MeasData from Measure and Data
// </etymology>
//
// <synopsis>
// MeasData contains the constant data
// necessary for precession, nutation and other
// <linkto class=Measure>Measure</linkto> related calculations.<br>
// Database (Table) related data, or data that can be changed by the user,
// is available in the <linkto class=MeasTable>MeasTable</linkto> class. <br>
// All data. apart from a set of simple constants:
// <srcblock>
//  MeasData::MJD2000
//  MeasData::MJDB1950
//  MeasData::MJDB1900
//  MeasData::MJDB1850
//  MeasData::TROPCEN
//  MeasData::JDCEN
//  MeasData::SECinDAY
// </srcblock>
// are obtained by calls to a method.
// This class contains no constructors or destructors, only static
// methods and (static) constants.
// <br> References:<br> Explanatory supplements to the Astronomical Almanac
// <br> C. Ron and J. Vondrak, Bull. Astron. Inst. Czechosl. 37, p96, 1986
// <br> M. Soma, Th. Hirayama and H. Kinoshita, Celest. Mech. 41, p389, 1988
// <br> V.S. Gubanov, Astron. Zh. 49, p1112, 1972 (English translation:
//      Sov. Astronomy - AJ, Vol. 16, No. 5, p. 907)
// </synopsis>
//
// <example>
// Usage examples can be found in <linkto class=Precession>Precession</linkto>
// </example>
//
// <motivation>
// To create a clean interface between the actual calculations and the
// methods to obtain the parameters for these calculations. Note that the
// tables are in general in the format and units found in the literature. This
// is to be able to easy check and change them. However, in the future
// re-arrangement could produce faster and more compact code.
// </motivation>
//
// <todo asof="1997/04/17">
//   <li> more precise data for VLBI and pulsar
// </todo>
 
class MeasData {
 public:
  // #  Constants
  //  General constants
  //  <group>
  //  MJD of J2000.0
  static const Double MJD2000;
  // MJD of B1950.0
  static const Double MJDB1950;
  // MJD of B1900.0
  static const Double MJDB1900;
  // MJD of B1850.0
  static const Double MJDB1850;
  // Length Tropical century
  static const Double TROPCEN;
  // Length Julian century
  static const Double JDCEN;
  // Length of day in sec
  static const Double SECinDAY;
  // </group>
 
  // # General Member Functions
 
  // Get the rotation matrices for galactic coordinates
  // <group>
  static const RotMatrix &GALtoB1950();
  static const RotMatrix &GALtoJ2000();
  static const RotMatrix &J2000toGAL();
  static const RotMatrix &B1950toGAL();
  // </group>
 
  // Get one of the 4 3x3 sub rotation matrices for B1950-J2000 conversions
  // <group>
  static const RotMatrix &MToB1950(uInt which);
  static const RotMatrix &MToJ2000(uInt which);
  // </group>
 
  // Get the solar semi diameter at 1 AU in rad
  static Double SunSemiDiameter();
 
  // J2000 obliquity
  static Double eps0J2000();
 
 private:
  // # Constructors
  //  Default constructor, NOT defined
  MeasData();
 
  // Copy assign, NOT defined
  MeasData &operator=(const MeasData &other);
 
  // # Destructor
  //   Destructor (NOT defined) and not declared to stop warning
  //  ~MeasData();
  // # General member functions
};
 
}  // namespace casacore
 
#endif