int main( const int argc, const char **argv)
{
char buff[100];
FILE *ifile;
time_t t0 = time( NULL);
if( argc != 2)
{
printf( "'jsattest' needs a command-line argument from 1 to 4,\n");
printf( "corresponding to the number of the Galilean satellite\n");
printf( "that is being tested.\n");
return( -1);
}
sprintf( buff, "j%s.txt", argv[1]);
ifile = fopen( buff, "rb");
if( !ifile)
{
printf( "%s not opened\n", buff);
return( -1);
}
printf( "All data in kilometers, in J2000 ecliptic coords\n");
printf( "Compiled %s %s; run %s", __DATE__, __TIME__, ctime( &t0));
printf( " JDE dx dy dz ");
printf( "x y z radial along\n");
while( fgets( buff, sizeof( buff), ifile))
if( strlen( buff) > 56 && !memcmp( buff + 37, "00:00:00.0000 (CT)", 18))
{
const double jd = atof( buff );
double loc[15], *tptr = loc + atoi( argv[1]) * 3 - 3;
double precess_matrix[9];
double j2000_loc[3], x, y, z, r;
if( !fgets( buff, sizeof( buff), ifile))
{
printf( "Read error");
return( -2);
}
x = atof( buff);
y = atof( buff + 24);
z = atof( buff + 47);
setup_ecliptic_precession( precess_matrix, 2000. + (jd - 2451545.) / 365., 2000.);
calc_jsat_loc( jd, loc, 15, 0L);
precess_vector( precess_matrix, tptr, j2000_loc);
j2000_loc[0] *= JRADIUS_IN_KM;
j2000_loc[1] *= JRADIUS_IN_KM;
j2000_loc[2] *= JRADIUS_IN_KM;
j2000_loc[0] -= x;
j2000_loc[1] -= y;
j2000_loc[2] -= z;
r = sqrt( x * x + y * y);
printf( "%10.2f %10.3f%10.3f%10.3f %11.2f%11.2f%11.2f %10.2f %10.2f\n", jd,
j2000_loc[0],
j2000_loc[1],
j2000_loc[2], x, y, z,
(j2000_loc[0] * x + j2000_loc[1] * y) / r,
(j2000_loc[1] * x - j2000_loc[0] * y) / r);
}
fclose( ifile);
return( 0);
}
int DLL_FUNC calc_ssat_loc( const double t, double DLLPTR *ssat,
const int sat_wanted, const long precision)
{
SAT_ELEMS elems;
ELEMENTS orbit;
double matrix[9];
const double t_years = (t - J2000) / 365.25;
if( precision == -1L) /* just checking version # */
return( 1);
if( sat_wanted < 0 || sat_wanted > PHOEBE)
return( -1);
elems.jd = t;
elems.sat_no = sat_wanted;
set_ssat_elems( &elems, &orbit);
setup_orbit_vectors( &orbit);
comet_posn_part_ii( &orbit, IGNORED_DOUBLE, elems.loc, NULL);
if( sat_wanted < RHEA) /* inner 4 satellites are returned in Saturnic */
{ /* coords so gotta rotate to B1950.0 */
rotate_vector( elems.loc, INCL0, 0);
rotate_vector( elems.loc, ASC_NODE0, 2);
}
/* After above, elems.loc is ecliptic 1950 coords */
rotate_vector( elems.loc, OBLIQUITY_1950, 0);
/* Now, elems.loc is equatorial 1950 coords */
#ifdef OUTPUT_IN_J2000
setup_precession( matrix, 1950., 2000);
precess_vector( matrix, elems.loc, ssat);
/* Now, ssats is equatorial J2000... */
rotate_vector( ssat, -OBLIQUITY_2000, 0);
/* And now, ssats is ecliptical J2000 */
#else
setup_precession( matrix, 1950., 2000. + t_years);
precess_vector( matrix, elems.loc, ssat);
/* Now, ssats is equatorial of epoch coords */
rotate_vector( ssat, -mean_obliquity( t_years / 100.), 0);
/* And now, ssats is ecliptical of epoch coords */
/* (which is what we really want anyway) */
#endif
return( 0);
}
void DLL_FUNC calc_triton_loc( const double jd, double *vect)
{
const double t_cent = (jd - J2000) / 36525.;
const double n = (359.28 + 54.308 * t_cent) * (PI / 180.);
const double t0 = 2433282.5;
const double theta = (151.401 + .57806 * (jd - t0) / 365.25) * (PI / 180.);
/* Semimajor axis is 488.49 arcseconds at one AU: */
const double semimajor = 488.49 * (PI / 180.) / 3600.;
const double longitude =
(200.913 + 61.2588532 * (jd - t0)) * (PI / 180.);
const double gamma = 158.996 * (PI / 180.);
/* Calculate longitude and latitude on invariable plane: */
const double lon_on_ip = theta + atan2( sin( longitude) * cos( gamma),
cos( longitude));
const double lat_on_ip = asin( sin( longitude) * sin( gamma));
/* Vectors defining invariable plane, expressed in B1950: */
double x_axis[3], y_axis[3], z_axis[3];
/* Vector defining Triton position in invariable plane space: */
double triton[3];
/* RA/dec of the pole: */
double ra_dec_p[2];
double matrix[9];
double vect_1950[3];
int i;
polar3_to_cartesian( triton, lon_on_ip, lat_on_ip);
ra_dec_p[0] = (298.72 * PI / 180.) + (2.58 * PI / 180.) * sin( n)
- (0.04 * PI / 180.) * sin( n + n);
ra_dec_p[1] = (42.63 * PI / 180.) - (1.90 * PI / 180.) * cos( n)
+ (0.01 * PI / 180.) * cos( n + n);
setup_precession( matrix, 1950., 2000.);
precess_ra_dec( matrix, ra_dec_p, ra_dec_p, 1);
polar3_to_cartesian( x_axis, ra_dec_p[0] + PI / 2., 0.);
polar3_to_cartesian( y_axis, ra_dec_p[0] + PI, PI / 2. - ra_dec_p[1]);
polar3_to_cartesian( z_axis, ra_dec_p[0], ra_dec_p[1]);
for( i = 0; i < 3; i++)
vect_1950[i] = semimajor * (x_axis[i] * triton[0] +
y_axis[i] * triton[1] + z_axis[i] * triton[2]);
precess_vector( matrix, vect_1950, vect);
}
