#include <stdio.h>

#include <math.h>

#include "d1cons.h"

#include "d1proto.h"

#include "d1typ.h"

#include "d1glob.h"

double vlsr(double time, double ra, double dec)

// calculate velocity of the local standard of rest

{

double decc, rac, vsun, vearth, x0, y0, z0, sunlong, soulong, soulat, x, y,

z, dp, rp, gwest, grad, gpole, lon0, ggwest;

decc = -(28.0 + 56.0 / 60.0) * PI / 180.0;

rac = (17.0 + 45.5 / 60.0) * PI / 12.0;

dp = 27.1 * PI / 180.0;

rp = (12.0 + 51.4 / 60.0) * PI / 12.0;

x0 = 20.0 * cos(18.0 * PI / 12.0) * cos(30.0 * PI / 180.0);

y0 = 20.0 * sin(18.0 * PI / 12.0) * cos(30.0 * PI / 180.0);

z0 = 20.0 * sin(30.0 * PI / 180.0); /* sun 20km/s towards ra=18h dec=30.0 */

vsun = -x0 * cos(ra) * cos(dec) - y0 * sin(ra) * cos(dec)

- z0 * sin(dec);

x0 = cos(ra) * cos(dec);

y0 = sin(ra) * cos(dec);

z0 = sin(dec);

x = x0;

y = y0 * cos(23.5 * PI / 180.0) + z0 * sin(23.5 * PI / 180.0);

z = z0 * cos(23.5 * PI / 180.0) - y0 * sin(23.5 * PI / 180.0);

soulat = atan2(z, sqrt(x * x + y * y));

soulong = atan2(y, x);

sunlong = (time * 360.0 / (365.2422 * 86400.0) + 280.0) * PI / 180.0; /* long=280 day 1 */

vearth = -30.0 * cos(soulat) * sin(sunlong - soulong);

gwest = cos(decc) * cos(rp - rac);

grad = cos(decc) * sin(rp - rac);

ggwest = gwest * sin(dp) - sin(decc) * cos(dp);

gpole = gwest * cos(dp) + sin(decc) * sin(dp);

lon0 = (atan2(ggwest, grad)) * 180.0 / PI;

gwest = cos(dec) * cos(rp - ra);

grad = cos(dec) * sin(rp - ra);

ggwest = gwest * sin(dp) - sin(dec) * cos(dp);

gpole = gwest * cos(dp) + sin(dec) * sin(dp);

d1.glat = (atan2(gpole, sqrt(ggwest * ggwest + grad * grad))) * 180.0 / PI;

d1.glon = (atan2(ggwest, grad)) * 180.0 / PI - lon0;

if (d1.glon < 0.0)

d1.glon += 360.0;

if (d1.glon > 360.0)

d1.glon += -360.0;

return vsun + vearth;

}

void GalactictoRadec(double glat, double glon, double *ra, double *dec)

/* galactic to radec 2000 epoch pole at 12h51.4 27.1 */

{

double a, xg, yg, zg, xr, yr, zr, d0, dp, r0, rp;

d0 = -(28.0 + 56.0 / 60.0) * PI / 180.0;

r0 = (17.0 + 45.5 / 60.0) * PI / 12.0;

dp = 27.1 * PI / 180.0;

rp = (12.0 + 51.4 / 60.0) * PI / 12.0;

zr = sin(d0);

xr = cos(r0 - rp) * cos(d0);

yr = sin(r0 - rp) * cos(d0);

xg = xr * sin(dp) - zr * cos(dp);

yg = yr;

a = atan2(yg, xg);

xg = cos((glon * PI / 180.0) + a) * cos(glat * PI / 180.0);

yg = sin((glon * PI / 180.0) + a) * cos(glat * PI / 180.0);

zg = sin(glat * PI / 180.0);

xr = xg * sin(dp) + zg * cos(dp);

yr = yg;

zr = zg * sin(dp) - xg * cos(dp);

*dec = atan2(zr, sqrt(xr * xr + yr * yr));

*ra = atan2(yr, xr) + rp;

if (*ra < 0)

*ra += TWOPI;

}

void moonradec(double time, double *ra, double *dec)

{

double ttime, asnode, amon, peri, em, aim, aam, vsm, alamm, moonsun, evn, var;

double x, y, z, xx, yy, zz, ram, decm, ha, inc;

/* calc moon ra and dec */

/* see notes and formulae Astronomical Almanac page D2 Moon, 1999 */

ttime = tosecs(1999, 0, 0, 0, 0); /* Jan 0 1999 */

ttime = (time - ttime) / 86400.00;

/* asnode=long of mean ascending node */

asnode = 144.452077 - 0.05295377 * ttime;

/* amon=omga plus mean lunar longitude */

amon = 69.167124 + 13.17639648 * ttime;

/* peri=asnode plus mean lunar longitude of perigee */

peri = 42.524057 + 0.11140353 * ttime;

/* moonsun is the elongation of moon from the sun */

moonsun = 149.940812 + 12.19074912 * ttime;

/* em is the eccentricity of lunar orbit */

em = 0.054900489;

/* aim=inclination of lunar orbit to ecliptic */

aim = 5.1453964 * PI / 180.0;

/* vsm=true anomaly */

/* the following are correction terms */

vsm = 2.0 * em * sin((amon - peri) * PI / 180.0); /* elliptical orbit */

evn = (1.274 / 57.3) * sin((2 * moonsun - (amon - peri)) * PI / 180.0); /* evection */

var = (0.658 / 57.3) * sin(2 * moonsun * PI / 180.0); /* variation */

alamm = (amon - asnode) * PI / 180.0 + vsm + evn + var;

x = cos(alamm);

y = sin(alamm);

z = 0;

xx = x;

yy = y * cos(aim);

zz = y * sin(aim);

ram = atan2(yy, xx) + asnode * PI / 180.0;

decm = atan2(zz, sqrt(xx * xx + yy * yy));

x = cos(ram) * cos(decm);

y = sin(ram) * cos(decm);

z = sin(decm);

inc = 23.45 * PI / 180.0;

xx = x;

yy = y * cos(inc) - z * sin(inc);

zz = z * cos(inc) + y * sin(inc);

/* aam is the semi-major axis of orbit earth radii */

aam = 60.2665;

z = zz - sin(d1.lat) / aam; /* correct for parallax */

ha = gst(time) - d1.lon;

x = xx - cos(d1.lat) * cos(ha) / aam;

y = yy - cos(d1.lat) * sin(ha) / aam;

*ra = atan2(y, x);

if (*ra < 0)

*ra += TWOPI;

*dec = atan2(z, sqrt(x * x + y * y));

}

/* Approximate Precession */

void precess(double rain, double decin, double *praout, double *pdecout, double epin, double epout)

{

*pdecout = decin + 0.0000972 * cos(rain) * (epout - epin);

*praout = rain + ((0.000223 + 0.0000972 * sin(rain) * tan(decin)) * (epout - epin));

}

void radec_azel(double ha, double dec, double latt, double *azs, double *elevs)

{

/* convert from sky to antenna coords (azel mount) */

/* input: ha,dec,latt

output: azs=azimuth of source

elevs=elevation of source

*/

double p, w, r, zen, north;

p = sin(dec);

w = sin(ha) * cos(dec);

r = cos(ha) * cos(dec);

zen = r * cos(latt) + p * sin(latt);

north = -r * sin(latt) + p * cos(latt);

*elevs = atan2(zen, sqrt(north * north + w * w));

*azs = atan2(-w, north);

if (*azs < 0)

*azs = *azs + TWOPI;

}

/* Calculate Sun ra and dec (approximate) */

/* see Astronomical Almanac page C24 Sun 1999 */

void sunradec(double time, double *ra, double *dec)

{

double n, g, lonn, ecl;

n = -365.5 + (time - tosecs(1999, 1, 0, 0, 0)) / 86400.0;

g = (357.528 + 0.9856003 * n) * PI / 180.0;

lonn = (280.460 + 0.9856474 * n + 1.915 * sin(g) + 0.02 * sin(2 * g)) * PI / 180.0;

ecl = (23.439 - 0.0000004 * n) * PI / 180.0;

*ra = atan2(sin(lonn) * cos(ecl), cos(lonn));

if (*ra < 0)

*ra += TWOPI;

*dec = asin(sin(lonn) * sin(ecl));

}

void azel_to_radec(double time, double az, double el, double *ra, double *dec)

// convert from azimuth and elevation to ra and dec

{

double north, west, zen, pole, rad, ha;

north = cos(az * PI / 180.0) * cos(el * PI / 180.0);

west = -sin(az * PI / 180.0) * cos(el * PI / 180.0);

zen = sin(el * PI / 180.0);

pole = north * cos(d1.lat) + zen * sin(d1.lat);

rad = zen * cos(d1.lat) - north * sin(d1.lat);

*dec = atan2(pole, sqrt(rad * rad + west * west));

ha = atan2(west, rad);

*ra = -ha + gst(time) - d1.lon;

if (*ra < 0)

*ra += TWOPI;

}