/* $Id: hststuff4.c,v 2.0 2001/09/14 19:05:06 garyb Exp $ */

#ifndef lint

static char vcid[] = "$Id: hststuff4.c,v 2.0 2001/09/14 19:05:06 garyb Exp $";

#endif /* lint */

#include "orbfit.h"

OBSERVATION obsarray[MAXOBS];

int nobs;

/*suffix for orbit-fit files*/

#define SUFFIX ".abg"

#define OBSCODE_HST 2000

#define TIME_STEP 0.2 /*time step (days) to locate oppangle*/

#define MAX_EPOCHS 100

#define LAT_MAX 5 /*only objects that are this close to ecliptic*/

#define PHASE_STEPS 20 /*number of phases for each object's orbit*/

#define ZA_LIMIT (90.*DTOR) /*maximum zenith angle for observations*/

#define NORBITS 10 /*number of orbits to observe*/

#define NFIELDS 4 /*number of fields to observe in cycle*/

#define EXP_PER_ORBIT 6 /*exposures per orbit*/

#define ASTROM_ERROR 0.004 /*uncertainty per visit */

#define VIS_TIME_STEP (1./24./60.) /*1-minute time steps to check visibility*/

#define OBSCODE_GRND 807 /*Where the followup observation will be*/

#define ERROR_GRND 0.2 /*Astrometric error on followup*/

#define OPP_GRND 225. /*opp angle to do pair of ground observations*/

char *help[] = {

"hststuff4: Show orbit uncertainties based upon a series of",

" HST observations, plus perhaps an additional ground-based",

" observation later on.",

" Try each object at several points in its orbit."

" usage: hststuff4 oppangle day1 day2 ... dayn",

" oppangle is opposition angle for first observation, which will",

" serve as zeropoint for positions.",

" dayn are days after first observation at which to calculate",

" input is list of objects. It is assumed that a file",

" with the name <object>.abg is present in current directory",

" output are predicted RA & Dec plus error ellipse & elongation.",

0

};

void

print_help(void)

{

int i;

for (i = 0; help[i] != 0; i++)

fprintf (stderr, "%s\n", help[i]);

exit (1);

}

extern void

deghms(double degr,

char *outbuff);

extern void

degdms(double degr,

char *outbuff);

/* routine to advance jd until oppangle is reached */

void

seek_oppangle(double oppangle,

double *jd,

PBASIS *p,

int obscode)

{

OBSERVATION futobs;

double nextopp, difflast, diffnext, lastopp;

futobs.obscode = obscode;

futobs.obstime = (*jd-jd0)*DAY;

futobs.xe = -999.; /* Force evaluation of earth3d */

predict_posn(p,NULL,&futobs,NULL);

lastopp = opposition_angle(&futobs)/DTOR;

do {

*jd += TIME_STEP;

futobs.obstime = (*jd-jd0)*DAY;

futobs.xe = -999.; /* Force evaluation of earth3d */

predict_posn(p,NULL,&futobs,NULL);

nextopp = opposition_angle(&futobs)/DTOR;

difflast = oppangle - lastopp;

while (difflast < -180.) difflast+=360.;

while (difflast > 180.) difflast-=360.;

diffnext = oppangle - nextopp;

while (diffnext < -180.) diffnext+=360.;

while (diffnext > 180.) diffnext-=360.;

lastopp = nextopp;

} while ( diffnext != 0. &&

(diffnext*difflast>0. || fabs(diffnext)>120.));

return;

}

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);

}