1998-09-15 04:26:07 +00:00
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/**************************************************************************
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* saturn.cxx
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* Written by Durk Talsma. Originally started October 1997, for distribution
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* with the FlightGear project. Version 2 was written in August and
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* September 1998. This code is based upon algorithms and data kindly
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* provided by Mr. Paul Schlyter. (pausch@saaf.se).
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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* (Log is kept at end of this file)
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**************************************************************************/
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1998-11-23 21:48:09 +00:00
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#ifdef __BORLANDC__
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# define exception c_exception
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#endif
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#include <math.h>
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1998-09-15 04:26:07 +00:00
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#include "saturn.hxx"
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/*************************************************************************
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* Saturn::Saturn(fgTIME *t)
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* Public constructor for class Saturn
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* Argument: The current time.
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* the hard coded orbital elements for Saturn are passed to
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* CelestialBody::CelestialBody();
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************************************************************************/
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Saturn::Saturn(fgTIME *t) :
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CelestialBody(113.6634, 2.3898000E-5,
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2.4886, -1.081E-7,
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339.3939, 2.9766100E-5,
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9.5547500, 0.000000,
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0.055546, -9.499E-9,
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316.9670, 0.03344422820, t)
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{
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}
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/*************************************************************************
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* void Saturn::updatePosition(fgTIME *t, Star *ourSun)
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*
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* calculates the current position of Saturn, by calling the base class,
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* CelestialBody::updatePosition(); The current magnitude is calculated using
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* a Saturn specific equation
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*************************************************************************/
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void Saturn::updatePosition(fgTIME *t, Star *ourSun)
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{
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CelestialBody::updatePosition(t, ourSun);
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double actTime = fgCalcActTime(t);
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double ir = 0.4897394;
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double Nr = 2.9585076 + 6.6672E-7*actTime;
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double B = asin (sin(declination) * cos(ir) -
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cos(declination) * sin(ir) *
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sin(rightAscension - Nr));
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double ring_magn = -2.6 * sin(fabs(B)) + 1.2 * pow(sin(B), 2);
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magnitude = -9.0 + 5*log10(r*R) + 0.044 * FV + ring_magn;
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}
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