/* Return the difference in ecliptic longitude between object & bary
* (e.g., 180 degrees is opposition).
* gives Sun - Target so it increases about 1 deg/day.
*/
double
opposition_angle(OBSERVATION *obs)
{
double lat, lonkbo, lonbary;
double xx, yy, zz, xec, yec, zec;
if (obs->xe < -9.) {
earth3d(obs->obstime, obs->obscode, &(obs->xe),&(obs->ye),&(obs->ze));
}
/* Get barycenter ecliptic longitude */
xx = xBary - obs->xe;
yy = yBary - obs->ye;
zz = zBary - obs->ze;
xyz_proj_to_ec(xx, yy, zz, &xec, &yec, &zec, lat0, lon0, NULL);
lonbary = atan2(yec,xec);
/* And the observation ecliptic longitude*/
proj_to_ec(obs->thetax, obs->thetay, &lat, &lonkbo, lat0, lon0, NULL);
lonkbo = lonbary - lonkbo;
while (lonkbo<0) lonkbo += 2*PI;
return lonkbo;
}
void
print_radec(OBSERVATION *obs, FILE *fptr)
{
/* Print out new observation */
/* Now transform to RA/DEC, via ecliptic*/
double ra, dec, lat, lon;
char rastring[20],decstring[20];
void deghms(double degr,
char *outbuff);
void degdms(double degr,
char *outbuff);
proj_to_ec(obs->thetax,obs->thetay,
&lat, &lon,
lat0, lon0, NULL);
ec_to_eq(lat, lon, &ra, &dec, NULL);
ra /= DTOR;
if (ra<0.) ra+= 360.;
dec /= DTOR;
deghms(ra,rastring);
degdms(dec,decstring);
fprintf(fptr,"%.4f %s %s %5.2f %d\n", obs->obstime/DAY + jd0,
rastring,decstring,obs->dthetax/ARCSEC,
obs->obscode);
return;
}
double *predict(char *abg_file, double jdate, int obscode)
{
PBASIS p;
OBSERVATION futobs;
struct date_time dt;
char inbuff[256], rastring[20], decstring[20];
char outbuff[256];
char *f_string;
double **covar,**sigxy,a,b,PA,**derivs;
double lat,lon,**covecl;
double ra,dec, **coveq;
double yr,mo,day,hr,mn,ss;
double xx,yy,xy,bovasqrd,det;
double distance;
static double result[6];
int i,nfields;
int iarg=1;
sigxy = dmatrix(1,2,1,2);
derivs = dmatrix(1,2,1,2);
covar = dmatrix(1,6,1,6);
covecl = dmatrix(1,2,1,2);
coveq = dmatrix(1,2,1,2);
result[0] = -1.0;
result[1] = -1.0;
result[2] = -1.0;
result[3] = -1.0;
result[4] = -1.0;
result[5] = -1.0;
if (read_abg(abg_file,&p,covar) ) {
fprintf(stderr, "Error input alpha/beta/gamma file %s\n",abg_file);
return result;
}
/* get observatory code */
futobs.obscode=obscode;
futobs.obstime=(jdate-jd0)*DAY;
futobs.xe = -999.; /* Force evaluation of earth3d */
distance = predict_posn(&p,covar,&futobs,sigxy);
/* Now transform to RA/DEC, via ecliptic*/
proj_to_ec(futobs.thetax,futobs.thetay,
&lat, &lon,
lat0, lon0, derivs);
/* map the covariance */
covar_map(sigxy, derivs, covecl, 2, 2);
/* Now to ICRS: */
ec_to_eq(lat, lon, &ra, &dec, derivs);
/* map the covariance */
covar_map(covecl, derivs, coveq, 2, 2);
/* Compute a, b, theta of error ellipse for output */
xx = coveq[1][1]*cos(dec)*cos(dec);
xy = coveq[1][2]*cos(dec);
yy = coveq[2][2];
PA = 0.5 * atan2(2.*xy,(xx-yy)) * 180./PI; /*go right to degrees*/
/* Put PA N through E */
PA = 90.-PA;
bovasqrd = (xx+yy-sqrt(pow(xx-yy,2.)+pow(2.*xy,2.)))
/ (xx+yy+sqrt(pow(xx-yy,2.)+pow(2.*xy,2.))) ;
det = xx*yy-xy*xy;
b = pow(det*bovasqrd,0.25);
a = pow(det/bovasqrd,0.25);
ra /= DTOR;
if (ra<0.) ra+= 360.;
dec /= DTOR;
result[0] = ra;
result[1] = dec;
result[2] = a/ARCSEC;
result[3] = b/ARCSEC;
result[4] = PA;
result[5] = distance;
return result;
}
int
main(int argc, char *argv[])
{
PBASIS p, pfit;
ORBIT o, ofit;
XVBASIS xv;
OBSERVATION futobs;
OBSERVATION *oo;
FILE *abgfile;
char inbuff[256],objname[256],fname[256];
double **covar,**sigxy;
double lat,lon;
int i,nfields;
double x[3], v[3], range;
double oppangle, epochs[MAX_EPOCHS], observe_day, period;
double x0, y0;
int nepochs, iphase, iexpose, iorbit;
int dof,ii;
double chisq, dbary, ddbary, vis_start, vis_end, jd;
double **covar_abg, **covar_xyz, **derivs, **covar_aei;
double launch; /*Date to start hunting for oppangle*/
if (argc<2) print_help();
oppangle = atof(argv[1]);
epochs[0]=0.;
for (i=2; i<argc; i++) epochs[i-1] = atof(argv[i]);
nepochs = argc-1;
futobs.obscode = OBSCODE_HST;
/* echo the command line to output */
printf("#");
for (i=0; i<argc; i++) printf(" %s",argv[i]);
{
#include <time.h>
time_t timettt;
time(&timettt);
/* note that ctime returns string with newline at end */
printf("\n#---%s",ctime(&timettt));
}
printf(
"# ID phi distance a e i "
" posn d a e i \n"
"# real fit err real fit err fit err NEW OBSERVATION:\n");
covar_abg = dmatrix(1,6,1,6);
covar_xyz = dmatrix(1,6,1,6);
covar_aei = dmatrix(1,6,1,6);
derivs = dmatrix(1,6,1,6);
sigxy = dmatrix(1,2,1,2);
covar = dmatrix(1,6,1,6);
/* Loop through input containing names of objects */
while ( fgets_nocomment(inbuff,255,stdin,NULL)!=NULL) {
sscanf(inbuff," %s ",objname);
strcpy(fname,objname);
strcat(fname,SUFFIX);
if (read_abg(fname,&p,covar)) {
fprintf(stderr, "Error reading alpha/beta/gamma file %s\n",fname);
exit(1);
}
/* look at several points around the orbital phase */
/* get orbital elements for this one */
pbasis_to_bary(&p, &xv, NULL);
orbitElements(&xv, &o);
period = pow(o.a, 1.5);
launch = jd0;
for (iphase=0; iphase<PHASE_STEPS; iphase++) {
/* Advance the object through its orbit by moving back time
* of perihelion (which is in days) */
o.T -= period/ (PHASE_STEPS*DAY);
/* Set up new orbit system based on this */
elements_to_pbasis(&o, launch, futobs.obscode, &p);
/* Now look for the day at which opp. angle meets spec */
observe_day = launch;
seek_oppangle(oppangle, &observe_day, &p, futobs.obscode);
futobs.obstime = (observe_day-jd0)*DAY;
futobs.xe = -999.; /* Force evaluation of earth3d */
predict_posn(&p,NULL,&futobs,NULL);
/* Now transform ecliptic*/
proj_to_ec(futobs.thetax,futobs.thetay,
&lat, &lon,
lat0, lon0, NULL);
/* Only keep objects close to ecliptic */
if (fabs(lat) > LAT_MAX*DTOR) continue;
/* Now reset the orbit and coordinate system to start here */
elements_to_pbasis(&o, observe_day, futobs.obscode, &p);
nobs = 0;
/* accumulate observations at all epochs */
for (i=0; i<nepochs; i++) {
/* Advance time until object is NOT visible */
vis_end = observe_day+epochs[i];
do {
vis_end+= VIS_TIME_STEP;
futobs.obstime = (vis_end-jd0)*DAY;
futobs.xe = -999.; /* Force evaluation of earth3d */
predict_posn(&p,NULL,&futobs,NULL);
} while (zenith_angle(&futobs) <= ZA_LIMIT) ;
for (iorbit=0; iorbit<NORBITS*NFIELDS; iorbit++) {
/* Then advance to first time it IS visible. */
vis_start = vis_end;
do {
vis_start+= VIS_TIME_STEP;
futobs.obstime = (vis_start-jd0)*DAY;
futobs.xe = -999.; /* Force evaluation of earth3d */
predict_posn(&p,NULL,&futobs,NULL);
} while (zenith_angle(&futobs) > ZA_LIMIT) ;
/* Now find end of visibility period */
vis_end = vis_start;
do {
vis_end+= VIS_TIME_STEP;
futobs.obstime = (vis_end-jd0)*DAY;
futobs.xe = -999.; /* Force evaluation of earth3d */
predict_posn(&p,NULL,&futobs,NULL);
} while (zenith_angle(&futobs) <= ZA_LIMIT) ;
vis_end -= VIS_TIME_STEP;
/* Only proceed if we are observing this field on this orbit*/
if (iorbit%NFIELDS !=0) continue;
/* Find middle of each exposure time */
jd = vis_start + (vis_end - vis_start)/(2.*EXP_PER_ORBIT);
for (iexpose=0; iexpose<EXP_PER_ORBIT; iexpose++,
jd+=(vis_end - vis_start)/EXP_PER_ORBIT) {
oo = &obsarray[nobs];
oo->obstime = (jd-jd0)*DAY;
oo->xe = -999.; /* Force evaluation of earth3d */
oo->obscode = OBSCODE_HST;
predict_posn(&p,NULL,oo,NULL);
oo->dthetax = oo->dthetay =
ASTROM_ERROR*sqrt(NORBITS*EXP_PER_ORBIT)*ARCSEC;
nobs++;
/*if (iphase==0) {
double ra, dec;
char rastring[40], decstring[40];
proj_to_ec(oo->thetax,oo->thetay,
&lat, &lon,
lat0, lon0, NULL);
ec_to_eq(lat, lon, &ra, &dec, NULL);
deghms(ra/DTOR,rastring);
degdms(dec/DTOR,decstring);
fprintf(stderr,"%f %s %s %.3f %d\n",jd, rastring, decstring,
oo->dthetax/ARCSEC,
OBSCODE_HST);
}*/
} /*exposure loop*/
} /*orbit loop*/
} /*observation-epoch loop */
/* Now fit the observations and report results */
ii=fit_observations(obsarray, nobs, &pfit, covar, &chisq, &dof, NULL);
/*fprintf(stderr,"# lat0 lon0 xBary yBary zBary JD0\n");
fprintf(stderr,"%12.7f %12.7f %10.7f %10.7f %10.7f %.6f\n",
lat0/DTOR,lon0/DTOR,xBary,yBary,zBary,jd0);
fprintf(stderr,"# Chi-squared of fit: %.2f DOF: %d\n",chisq,dof);
fprintf(stderr,"%11.8f %11.8f %11.8f %11.8f %11.8f %11.8f\n",
pfit.a,pfit.adot,pfit.b,pfit.bdot, pfit.g, pfit.gdot);
print_matrix(stderr,covar,6,6);
*/
pbasis_to_bary(&pfit, &xv, derivs);
orbitElements(&xv, &ofit);
/* Note that below is distance at jd0=abg file zpoint, NOT at
* first observation, which is some part of a year later.
*/
dbary = sqrt(xBary*xBary + yBary*yBary + pow(zBary-1/pfit.g,2.));
ddbary = dbary*dbary*sqrt(covar[5][5]);
/* Get elements and covariance matrix thereof */
covar_map(covar, derivs, covar_xyz,6,6);
aei_derivs(&xv, derivs);
covar_map(covar_xyz, derivs, covar_aei,6,6);
/*Print out some info & uncertainties */
printf("%8s %2d %5.2f +- %4.2f %1d %5.2f %5.2f +- %4.2f %5.3f %5.3f +- %5.3f"
" %7.1f +- %4.1f",
objname, iphase,
dbary, ddbary, ii,
o.a, ofit.a, sqrt(covar_aei[1][1]),
o.e, ofit.e, sqrt(covar_aei[2][2]),
ofit.i, sqrt(covar_aei[3][3])/DTOR);
/* Now get the positional uncertainty at a future date, and
* refit after two extra measurements from ground
*/
oo = &obsarray[nobs];
nobs++;
jd = observe_day + OPP_GRND - oppangle;
oo->obstime = (jd-jd0)*DAY;
oo->obscode = OBSCODE_GRND;
oo->xe = -999.;
predict_posn(&pfit,covar,oo,sigxy);
/*if (iphase==0) {
fprintf(stderr,"Prediction on %.2f, posn %.2f %.2f unc %.2f %.2f\n",
jd, oo->thetax/ARCSEC, oo->thetay/ARCSEC,
sqrt(sigxy[1][1])/ARCSEC, sqrt(sigxy[2][2])/ARCSEC);
print_matrix(stderr,covar,6,6);
}*/
{
/* Compute a, of error ellipse for output */
double xx, yy, xy, bovasqrd, det, a;
xx = sigxy[1][1];
yy = sigxy[2][2];
xy = sigxy[1][2];
bovasqrd = (xx+yy-sqrt(pow(xx-yy,2.)+pow(2.*xy,2.)))
/ (xx+yy+sqrt(pow(xx-yy,2.)+pow(2.*xy,2.))) ;
det = xx*yy-xy*xy;
a = pow(det/bovasqrd,0.25);
printf(" %5.1f", a/ARCSEC);
}
/* Now re-fit with two additional observations */
predict_posn(&p,NULL,oo,NULL);
oo->dthetax = oo->dthetay = ERROR_GRND * ARCSEC;
oo = &obsarray[nobs];
nobs++;
oo->obstime = obsarray[nobs-2].obstime + DAY;
oo->obscode = OBSCODE_GRND;
oo->xe = -999.;
predict_posn(&p,NULL,oo,NULL);
oo->dthetax = oo->dthetay = ERROR_GRND * ARCSEC;
ii = fit_observations(obsarray, nobs, &pfit, covar, &chisq, &dof, NULL);
pbasis_to_bary(&pfit, &xv, derivs);
orbitElements(&xv, &ofit);
dbary = sqrt(xBary*xBary + yBary*yBary + pow(zBary-1/pfit.g,2.));
ddbary = dbary*dbary*sqrt(covar[5][5]);
/* Get elements and covariance matrix thereof */
covar_map(covar, derivs, covar_xyz,6,6);
aei_derivs(&xv, derivs);
covar_map(covar_xyz, derivs, covar_aei,6,6);
/*Print out some info & uncertainties */
printf(" %5.2f +- %4.2f %1d %5.2f +- %4.2f %5.3f +- %5.3f"
" %7.1f +- %4.1f \n",
dbary, ddbary, ii,
ofit.a, sqrt(covar_aei[1][1]),
ofit.e, sqrt(covar_aei[2][2]),
ofit.i, sqrt(covar_aei[3][3])/DTOR);
} /*phase loop */
} /*object loop*/
exit(0);
}
int
main(int argc, char *argv[])
{
PBASIS p;
OBSERVATION futobs;
struct date_time dt;
char inbuff[256],rastring[20],decstring[20];
double **covar,**sigxy,a,b,PA,**derivs;
double lat,lon,**covecl;
double ra,dec, **coveq;
double yr,mo,day,hr,mn,ss;
double xx,yy,xy,bovasqrd,det;
int i,nfields;
int iarg=1;
if (argc>1 && *argv[1]=='^') print_help();
if (read_options(&iarg, argc, argv)) print_help();
if (iarg>=argc) print_help();
/* echo the command line to output */
printf("#");
for (i=0; i<argc; i++) printf(" %s",argv[i]);
{
#include <time.h>
time_t timettt;
time(&timettt);
/* note that ctime returns string with newline at end */
printf("\n#---%s",ctime(&timettt));
}
sigxy = dmatrix(1,2,1,2);
derivs = dmatrix(1,2,1,2);
covar = dmatrix(1,6,1,6);
covecl = dmatrix(1,2,1,2);
coveq = dmatrix(1,2,1,2);
if (read_abg(argv[iarg],&p,covar)) {
fprintf(stderr, "Error input alpha/beta/gamma file %s\n",argv[iarg]);
exit(1);
}
/* get observatory code */
fprintf (stderr,"Enter observatory code:\n");
if (fgets_nocomment(inbuff,255,stdin,NULL)==NULL
|| sscanf(inbuff,"%d",&futobs.obscode)!=1) {
fprintf(stderr,"Error reading observatory code\n");
exit(1);
}
printf("# For observations at site %d\n"
"# x/RA y/DEC "
"err_a err_b err_pa\n",futobs.obscode);
fprintf (stderr,"Enter JD's or Y M D ... of observations, -1 to quit:\n");
while ( fgets_nocomment(inbuff,255,stdin,NULL)!=NULL) {
nfields=sscanf(inbuff,"%lf %lf %lf %lf %lf %lf",
&yr,&mo,&day,&hr,&mn,&ss);
if (nfields==0 ) {
fprintf(stderr,"Error on time spec:\n->%s\n",inbuff);
exit(1);
} else if (yr<0.) {
/*done*/
exit(0);
} else if (nfields==1 || nfields==2) {
/* Got a JD. (probably...)*/
futobs.obstime = (yr-jd0)*DAY;
} else {
dt.y = yr;
dt.mo = mo;
dt.d = day;
if (nfields>=4) dt.h = hr; else dt.h=0.;
if (nfields>=5) dt.mn = mn; else dt.mn=0.;
if (nfields>=6) dt.s = ss; else dt.s=0.;
futobs.obstime = (date_to_jd(dt)-jd0)*DAY;
}
futobs.xe = -999.; /* Force evaluation of earth3d */
printf("At time= %s",inbuff);
predict_posn(&p,covar,&futobs,sigxy);
printf("# Solar Elongation = %.2f Opp angle = %.2f\n",
elongation(&futobs)/DTOR,opposition_angle(&futobs)/DTOR);
/* Compute a, b, theta of error ellipse for output */
xx = sigxy[1][1];
yy = sigxy[2][2];
xy = sigxy[1][2];
PA = 0.5 * atan2(2.*xy,(xx-yy)) * 180./PI; /*go right to degrees*/
/* Adjust for PA to be N through E, */
PA = PA-90;
if (PA<-90.) PA += 180.;
bovasqrd = (xx+yy-sqrt(pow(xx-yy,2.)+pow(2.*xy,2.)))
/ (xx+yy+sqrt(pow(xx-yy,2.)+pow(2.*xy,2.))) ;
det = xx*yy-xy*xy;
b = pow(det*bovasqrd,0.25);
a = pow(det/bovasqrd,0.25);
printf("Cum. ecliptic posn: %10.4f %10.4f %8.2f %8.2f %7.2f\n",
futobs.thetax/ARCSEC, futobs.thetay/ARCSEC,
a/ARCSEC,b/ARCSEC,PA);
/* Now transform to RA/DEC, via ecliptic*/
proj_to_ec(futobs.thetax,futobs.thetay,
&lat, &lon,
lat0, lon0, derivs);
/* map the covariance */
covar_map(sigxy, derivs, covecl, 2, 2);
/* Now to ICRS: */
ec_to_eq(lat, lon, &ra, &dec, derivs);
/* map the covariance */
covar_map(covecl, derivs, coveq, 2, 2);
/* Compute a, b, theta of error ellipse for output */
xx = coveq[1][1]*cos(dec)*cos(dec);
xy = coveq[1][2]*cos(dec);
yy = coveq[2][2];
PA = 0.5 * atan2(2.*xy,(xx-yy)) * 180./PI; /*go right to degrees*/
/* Put PA N through E */
PA = 90.-PA;
bovasqrd = (xx+yy-sqrt(pow(xx-yy,2.)+pow(2.*xy,2.)))
/ (xx+yy+sqrt(pow(xx-yy,2.)+pow(2.*xy,2.))) ;
det = xx*yy-xy*xy;
b = pow(det*bovasqrd,0.25);
a = pow(det/bovasqrd,0.25);
ra /= DTOR;
if (ra<0.) ra+= 360.;
dec /= DTOR;
deghms(ra,rastring);
degdms(dec,decstring);
printf("ICRS position: %s %s %10.4f %10.4f %7.2f\n",
rastring,decstring,a/ARCSEC,b/ARCSEC,PA);
}
exit(0);
}
