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 Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
24 **************************************************************************/
27 # define exception c_exception
33 /*************************************************************************
34 * Saturn::Saturn(double mjd)
35 * Public constructor for class Saturn
36 * Argument: The current time.
37 * the hard coded orbital elements for Saturn are passed to
38 * CelestialBody::CelestialBody();
39 ************************************************************************/
40 Saturn::Saturn(double mjd) :
41 CelestialBody(113.6634, 2.3898000E-5,
43 339.3939, 2.9766100E-5,
46 316.9670, 0.03344422820, mjd)
50 CelestialBody(113.6634, 2.3898000E-5,
52 339.3939, 2.9766100E-5,
55 316.9670, 0.03344422820)
59 /*************************************************************************
60 * void Saturn::updatePosition(double mjd, Star *ourSun)
62 * calculates the current position of Saturn, by calling the base class,
63 * CelestialBody::updatePosition(); The current magnitude is calculated using
64 * a Saturn specific equation
65 *************************************************************************/
66 void Saturn::updatePosition(double mjd, Star *ourSun)
68 CelestialBody::updatePosition(mjd, ourSun);
70 double actTime = sgCalcActTime(mjd);
71 double ir = 0.4897394;
72 double Nr = 2.9585076 + 6.6672E-7*actTime;
73 double B = asin (sin(declination) * cos(ir) -
74 cos(declination) * sin(ir) *
75 sin(rightAscension - Nr));
76 double ring_magn = -2.6 * sin(fabs(B)) + 1.2 * pow(sin(B), 2);
77 magnitude = -9.0 + 5*log10(r*R) + 0.044 * FV + ring_magn;