void palOapqk	(	const char *	type,
		double	ob1,
		double	ob2,
		const double	aoprms[14],
		double *	rap,
		double *	dap
	)

Definition at line 150 of file palOapqk.c.

References palDcc2s(), palDcs2c(), palDranrm(), and palRefro().

Referenced by palOap(), and t_aop().

                                           {

  /*  breakpoint for fast/slow refraction algorithm:
   *  zd greater than arctan(4), (see palRefco routine)
   *  or vector z less than cosine(arctan(z)) = 1/sqrt(17) */
  const double zbreak = 0.242535625;

  char c;
  double c1,c2,sphi,cphi,st,ce,xaeo,yaeo,zaeo,v[3],
    xmhdo,ymhdo,zmhdo,az,sz,zdo,tz,dref,zdt,
    xaet,yaet,zaet,xmhda,ymhda,zmhda,diurab,f,hma;

  /*  coordinate type */
  c = type[0];

  /*  coordinates */
  c1 = ob1;
  c2 = ob2;

  /*  sin, cos of latitude */
  sphi = aoprms[1];
  cphi = aoprms[2];

  /*  local apparent sidereal time */
  st = aoprms[13];

  /*  standardise coordinate type */
  if (c == 'r' || c == 'R') {
    c = 'r';
  } else if (c == 'h' || c == 'H') {
    c = 'h';
  } else {
    c = 'a';
  }

  /*  if az,zd convert to cartesian (s=0,e=90) */
  if (c == 'a') {
    ce = sin(c2);
    xaeo = -cos(c1)*ce;
    yaeo = sin(c1)*ce;
    zaeo = cos(c2);
  } else {

    /*     if ra,dec convert to ha,dec */
    if (c == 'r') {
      c1 = st-c1;
    }

    /*     to cartesian -ha,dec */
    palDcs2c( -c1, c2, v );
    xmhdo = v[0];
    ymhdo = v[1];
    zmhdo = v[2];

    /*     to cartesian az,el (s=0,e=90) */
    xaeo = sphi*xmhdo-cphi*zmhdo;
    yaeo = ymhdo;
    zaeo = cphi*xmhdo+sphi*zmhdo;
  }

  /*  azimuth (s=0,e=90) */
  if (xaeo != 0.0 || yaeo != 0.0) {
    az = atan2(yaeo,xaeo);
  } else {
    az = 0.0;
  }

  /*  sine of observed zd, and observed zd */
  sz = sqrt(xaeo*xaeo+yaeo*yaeo);
  zdo = atan2(sz,zaeo);

  /*
   *  refraction
   *  ---------- */

  /*  large zenith distance? */
  if (zaeo >= zbreak) {

    /*     fast algorithm using two constant model */
    tz = sz/zaeo;
    dref = (aoprms[10]+aoprms[11]*tz*tz)*tz;

  } else {

    /*     rigorous algorithm for large zd */
    palRefro(zdo,aoprms[4],aoprms[5],aoprms[6],aoprms[7],
             aoprms[8],aoprms[0],aoprms[9],1e-8,&dref);
  }

  zdt = zdo+dref;

  /*  to cartesian az,zd */
  ce = sin(zdt);
  xaet = cos(az)*ce;
  yaet = sin(az)*ce;
  zaet = cos(zdt);

  /*  cartesian az,zd to cartesian -ha,dec */
  xmhda = sphi*xaet+cphi*zaet;
  ymhda = yaet;
  zmhda = -cphi*xaet+sphi*zaet;

  /*  diurnal aberration */
  diurab = -aoprms[3];
  f = (1.0-diurab*ymhda);
  v[0] = f*xmhda;
  v[1] = f*(ymhda+diurab);
  v[2] = f*zmhda;

  /*  to spherical -ha,dec */
  palDcc2s(v,&hma,dap);

  /*  Right Ascension */
  *rap = palDranrm(st+hma);

}

Here is the call graph for this function:

Here is the caller graph for this function: