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00001 //# Aberration.h: Aberration class 00002 //# Copyright (C) 1995,1996,1997,1998 00003 //# Associated Universities, Inc. Washington DC, USA. 00004 //# 00005 //# This library is free software; you can redistribute it and/or modify it 00006 //# under the terms of the GNU Library General Public License as published by 00007 //# the Free Software Foundation; either version 2 of the License, or (at your 00008 //# option) any later version. 00009 //# 00010 //# This library is distributed in the hope that it will be useful, but WITHOUT 00011 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 00012 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public 00013 //# License for more details. 00014 //# 00015 //# You should have received a copy of the GNU Library General Public License 00016 //# along with this library; if not, write to the Free Software Foundation, 00017 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA. 00018 //# 00019 //# Correspondence concerning AIPS++ should be addressed as follows: 00020 //# Internet email: aips2-request@nrao.edu. 00021 //# Postal address: AIPS++ Project Office 00022 //# National Radio Astronomy Observatory 00023 //# 520 Edgemont Road 00024 //# Charlottesville, VA 22903-2475 USA 00025 //# 00026 //# 00027 //# $Id: Aberration.h 20739 2009-09-29 01:15:15Z Malte.Marquarding $ 00028 00029 #ifndef MEASURES_ABERRATION_H 00030 #define MEASURES_ABERRATION_H 00031 00032 //# Includes 00033 #include <casa/aips.h> 00034 #include <casa/Quanta/MVPosition.h> 00035 00036 00037 namespace casa { //# NAMESPACE CASA - BEGIN 00038 00039 // <summary> 00040 // Aberration class and calculations 00041 // </summary> 00042 00043 // <use visibility=export> 00044 00045 // <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tMeasMath" demos=""> 00046 // </reviewed> 00047 00048 // <prerequisite> 00049 // <li> <linkto class=Measure>Measure</linkto> class, 00050 // especially <linkto class=MEpoch>MEpoch</linkto> 00051 // <li> <linkto class=MeasData>MeasData</linkto> class for constants 00052 // </prerequisite> 00053 // 00054 // <etymology> 00055 // Aberration 00056 // </etymology> 00057 // 00058 // <synopsis> 00059 // Aberration forms the class for Aberration calculations. It is a simple 00060 // container with the selected method, and the mean epoch.<br> 00061 // The method is selected from one of the following: 00062 // <ul> 00063 // <li> Aberration::STANDARD (at 1995/09/04 the IAU1980 definition) 00064 // <li> Aberration::NONE 00065 // <li> Aberration::B1950 00066 // </ul> 00067 // Epochs can be specified as the MJD (with defined constants MeasData::MJD2000 00068 // and MeasData::MJDB1950 or the actual MJD), 00069 // leading to the following constructors: 00070 // <ul> 00071 // <li> Aberration() default; assuming JD2000, IAU1980 00072 // <li> Aberration(method) assuming the correct default epoch of 00073 // JD2000 or B1950 00074 // <li> Aberration(method,epoch) with epoch Double(MJD). 00075 // </ul> 00076 // Actual Aberration for a certain Epoch is calculated by the () operator 00077 // as Aberration(epoch), with epoch Double MJD, values returned as an 00078 // MVPosition.<br> 00079 // The derivative (d<sup>-1</sup>) can be obtained as well by 00080 // derivative(epoch).<br> 00081 // The following details can be set with the 00082 // <linkto class=Aipsrc>Aipsrc</linkto> mechanism: 00083 // <ul> 00084 // <li> measures.aberration.d_interval: approximation interval as time 00085 // (fraction of days is default unit) over which linear approximation 00086 // is used 00087 // <li> measures.aberration.b_usejpl: use the JPL database values for IAU1980. 00088 // Else analytical expression, relative error about 10<sup>-9</sup> 00089 // Note that the JPL database to be used can be set with 00090 // measures.jpl.ephemeris (at the moment of writing DE200 (default), 00091 // or DE405). If using the JPL database, the d_interval (and the 00092 // output of derivative()) are irrelevant. 00093 // </ul> 00094 // </synopsis> 00095 // 00096 // <example> 00097 // </example> 00098 // 00099 // <motivation> 00100 // To calculate the Aberration angles. An alternate route could have been 00101 // a global function, but having a simple container allows 00102 // caching of some calculations for speed.<br> 00103 // Using MJD (JD-2400000.5) rather than JD is for precision reasons. 00104 // </motivation> 00105 // 00106 // <todo asof="1997/12/02"> 00107 // </todo> 00108 00109 class Aberration 00110 { 00111 public: 00112 //# Constants 00113 // Interval to be used for linear approximation (in days) 00114 static const Double INTV; 00115 00116 //# Enumerations 00117 // Types of known Aberration calculations (at 1995/09/04 STANDARD == IAU1980) 00118 enum AberrationTypes {STANDARD,NONE,B1950}; 00119 00120 //# Constructors 00121 // Default constructor, generates default J2000 Aberration identification 00122 Aberration(); 00123 // Copy constructor 00124 Aberration(const Aberration &other); 00125 // Constructor with type 00126 Aberration(AberrationTypes type); 00127 // Copy assignment 00128 Aberration &operator=(const Aberration &other); 00129 00130 //# Destructor 00131 ~Aberration(); 00132 00133 //# Operators 00134 // Operator () calculates the Aberration direction cosine vector 00135 const MVPosition &operator()(Double epoch); 00136 00137 //# General Member Functions 00138 // Return derivative of Aberration (d<sup>-1</sup>) w.r.t. time 00139 const MVPosition &derivative (Double epoch); 00140 00141 // Re-initialise Aberration object 00142 // <group> 00143 void init(); 00144 void init(AberrationTypes type); 00145 // </group> 00146 00147 // Refresh calculations 00148 void refresh(); 00149 00150 private: 00151 //# Data menbers 00152 // Method to be used 00153 AberrationTypes method; 00154 // Check epoch for linear approximation 00155 Double checkEpoch; 00156 // Cached calculated angles 00157 Double aval[3]; 00158 // Cached derivatives 00159 Double dval[3]; 00160 // To be able to use referenced results in simple calculations, a circular 00161 // result buffer is used. 00162 // Current buffer pointer. 00163 Int lres; 00164 // Last calculation 00165 MVPosition result[4]; 00166 // Interpolation interval 00167 static uInt interval_reg; 00168 // JPL use 00169 static uInt usejpl_reg; 00170 00171 //# Member functions 00172 // Copy 00173 void copy(const Aberration &other); 00174 // Fill an empty copy 00175 void fill(); 00176 // Calculate Aberration angles for time t 00177 void calcAber(Double t); 00178 }; 00179 00180 00181 } //# NAMESPACE CASA - END 00182 00183 #endif 00184 00185