1 /**************************************************************************
3 * Written by Durk Talsma. Originally started October 1997, for distribution
4 * with the FlightGear project. Version 2 was written in August and
5 * September 1998. This code is based upon algorithms and data kindly
6 * provided by Mr. Paul Schlyter. (pausch@saaf.se).
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
23 **************************************************************************/
26 # define exception c_exception
32 /*************************************************************************
33 * Saturn::Saturn(double mjd)
34 * Public constructor for class Saturn
35 * Argument: The current time.
36 * the hard coded orbital elements for Saturn are passed to
37 * CelestialBody::CelestialBody();
38 ************************************************************************/
39 Saturn::Saturn(double mjd) :
40 CelestialBody(113.6634, 2.3898000E-5,
42 339.3939, 2.9766100E-5,
45 316.9670, 0.03344422820, mjd)
49 CelestialBody(113.6634, 2.3898000E-5,
51 339.3939, 2.9766100E-5,
54 316.9670, 0.03344422820)
58 /*************************************************************************
59 * void Saturn::updatePosition(double mjd, Star *ourSun)
61 * calculates the current position of Saturn, by calling the base class,
62 * CelestialBody::updatePosition(); The current magnitude is calculated using
63 * a Saturn specific equation
64 *************************************************************************/
65 void Saturn::updatePosition(double mjd, Star *ourSun)
67 CelestialBody::updatePosition(mjd, ourSun);
69 double actTime = sgCalcActTime(mjd);
70 double ir = 0.4897394;
71 double Nr = 2.9585076 + 6.6672E-7*actTime;
72 double B = asin (sin(declination) * cos(ir) -
73 cos(declination) * sin(ir) *
74 sin(rightAscension - Nr));
75 double ring_magn = -2.6 * sin(fabs(B)) + 1.2 * pow(sin(B), 2);
76 magnitude = -9.0 + 5*log10(r*R) + 0.044 * FV + ring_magn;