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Diffstat (limited to 'kstars/kstars/kssun.cpp')
| -rw-r--r-- | kstars/kstars/kssun.cpp | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/kstars/kstars/kssun.cpp b/kstars/kstars/kssun.cpp new file mode 100644 index 00000000..ce3a60d1 --- /dev/null +++ b/kstars/kstars/kssun.cpp @@ -0,0 +1,168 @@ +/*************************************************************************** + kssun.cpp - K Desktop Planetarium + ------------------- + begin : Sun Jul 22 2001 + copyright : (C) 2001 by Jason Harris + email : jharris@30doradus.org + ***************************************************************************/ + +/*************************************************************************** + * * + * 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. * + * * + ***************************************************************************/ + +#include <math.h> +#include <qdatetime.h> + +#include "kssun.h" +#include "ksutils.h" +#include "ksnumbers.h" +#include "kstarsdatetime.h" + +KSSun::KSSun( KStarsData *kd, QString fn, double pSize ) : KSPlanet( kd, I18N_NOOP( "Sun" ), fn, pSize ) { + /* + JD0 = 2447892.5; //Jan 1, 1990 + eclong0 = 279.403303; //mean ecliptic longitude at JD0 + plong0 = 282.768422; //longitude of sun at perigee for JD0 + e0 = 0.016713; //eccentricity of Earth's orbit at JD0 + */ + setMag( -26.73 ); +} + +bool KSSun::loadData() { +// kdDebug() << k_funcinfo << endl; + return (odm.loadData("earth") != 0); +} + +bool KSSun::findGeocentricPosition( const KSNumbers *num, const KSPlanetBase *Earth ) { + if (Earth) { + // + // For the precision we need, the earth's orbit is circular. + // So don't bother to iterate like KSPlanet does. Just subtract + // The current delay and recompute (once). + // + double delay = (.0057755183 * Earth->rsun()) / 365250.0; + + // + // MHH 2002-02-04 I don't like this. But it avoids code duplication. + // Maybe we can find a better way. + // + const KSPlanet *pEarth = dynamic_cast<const KSPlanet *>(Earth); + /* FIXME: if you use pEarth at some point again, make sure you + check for 0L after the dynamic_cast! */ + EclipticPosition trialpos; + pEarth->calcEcliptic(num->julianMillenia() - delay, trialpos); + + setEcLong( trialpos.longitude.Degrees() + 180.0 ); + setEcLong( ecLong()->reduce().Degrees() ); + setEcLat( -1.0*trialpos.latitude.Degrees() ); + + } else { + double sum[6]; + dms EarthLong, EarthLat; //heliocentric coords of Earth + OrbitDataColl * odc; + double T = num->julianMillenia(); //Julian millenia since J2000 + double Tpow[6]; + + Tpow[0] = 1.0; + for (int i=1; i<6; ++i) { + Tpow[i] = Tpow[i-1] * T; + } + //First, find heliocentric coordinates + + if (!(odc = odm.loadData("earth"))) return false; + + //Ecliptic Longitude + for (int i=0; i<6; ++i) { + sum[i] = 0.0; + for (uint j = 0; j < odc->Lon[i].size(); ++j) { + sum[i] += odc->Lon[i][j]->A * cos( odc->Lon[i][j]->B + odc->Lon[i][j]->C*T ); + } + sum[i] *= Tpow[i]; + //kdDebug() << name() << " : sum[" << i << "] = " << sum[i] <<endl; + } + + EarthLong.setRadians( sum[0] + sum[1] + sum[2] + + sum[3] + sum[4] + sum[5] ); + EarthLong.setD( EarthLong.reduce().Degrees() ); + + //Compute Ecliptic Latitude + for (int i=0; i<6; ++i) { + sum[i] = 0.0; + for (uint j = 0; j < odc->Lat[i].size(); ++j) { + sum[i] += odc->Lat[i][j]->A * cos( odc->Lat[i][j]->B + odc->Lat[i][j]->C*T ); + } + sum[i] *= Tpow[i]; + } + + + EarthLat.setRadians( sum[0] + sum[1] + sum[2] + sum[3] + + sum[4] + sum[5] ); + + //Compute Heliocentric Distance + for (int i=0; i<6; ++i) { + sum[i] = 0.0; + for (uint j = 0; j < odc->Dst[i].size(); ++j) { + sum[i] += odc->Dst[i][j]->A * cos( odc->Dst[i][j]->B + odc->Dst[i][j]->C*T ); + } + sum[i] *= Tpow[i]; + } + + ep.radius = sum[0] + sum[1] + sum[2] + sum[3] + sum[4] + sum[5]; + + setEcLong( EarthLong.Degrees() + 180.0 ); + setEcLong( ecLong()->reduce().Degrees() ); + setEcLat( -1.0*EarthLat.Degrees() ); + } + + //Finally, convert Ecliptic coords to Ra, Dec. Ecliptic latitude is zero, by definition + EclipticToEquatorial( num->obliquity() ); + + nutate(num); + aberrate(num); + + // We obtain the apparent geocentric ecliptic coordinates. That is, after + // nutation and aberration have been applied. + EquatorialToEcliptic( num->obliquity() ); + + //Determine the position angle + findPA( num ); + + return true; +} + +long double KSSun::springEquinox(int year) { + return equinox(year, 18, 3, 0.); +} + +long double KSSun::summerSolstice(int year) { + return equinox(year, 18, 6, 90.); +} + +long double KSSun::autumnEquinox(int year) { + return equinox(year, 19, 9, 180.); +} + +long double KSSun::winterSolstice(int year) { + return equinox(year, 18, 12, 270.); +} + +long double KSSun::equinox(int year, int d, int m, double angle) { + long double jd0[5]; + long double eclipticLongitude[5]; + + for(int i = 0; i<5; ++i) { + jd0[i] = KStarsDateTime( ExtDate(year,m,d+i), QTime(0,0,0) ).djd(); + KSNumbers *ksn = new KSNumbers(jd0[i]); + //FIXME this is the Earth position + findGeocentricPosition( ksn ); + delete ksn; + eclipticLongitude[i] = (long double)ecLong()->Degrees(); + } + + return KSUtils::lagrangeInterpolation( eclipticLongitude, jd0, 5, angle ); +} |