" + descrip + "
"; // str += "" + "
"; if (obj>=0 && obj<100) str += "" + line1 + "\n" + line2 + "\n" + line3 + "\n";
document.write(str);
} // end pheader()
function pbottom(line2) {
// finish the page
var line3="";
for (var i=0; i<(line2.length+4); i++) line3 += "-";
var str = line3 + "\n";
// str += "\n";
// str += "";
document.write(str);
document.close();
// pwin.focus();
} // end pbottom()
// 'l_events' is array of records holding all detected events. Each record comprising:
// 1. time in JD format; 2. first object; 3. second object;
// 4. event type: 0=conj, 1=summer solstice/1st quarter/quadrature, 2=aut. equinox/oppos./Full Moon,
// 3=winter solstice/last quarter/quadrature, 4=max elong, 8=peri/apo event;
// 5. angle or distance; 6. position angle or peri/apo flag
function longitudeEvents(obs,jdmax,l_events,sel) {
// Find equinoxes, solstices, moon phases, oppositions, mutual and solar conjunctions
// For each day in timespan detect if an event takes place by comparing longitudes
if (!sel.conj_sol && !sel.conj_moon && !sel.conj_planet && !sel.quadrature) {
var objects = [SUN];
if (sel.phase) objects[1] = MOON;
}
else {
var objects = [SUN, MOON, MERCURY, VENUS, MARS, JUPITER, SATURN, URANUS, NEPTUNE];
if (!sel.phase && !sel.conj_moon) objects.splice(1,1); // remove moon
}
var odat0 = new Array(); // positions of all objects at start of day
var odat2 = new Array(); // positions at end of day
var jday = jd0(obs.year,obs.month,obs.day) + obs.tz/1440.0;
for (var i in objects) { var p = objects[i]; odat0[p] = PlanetAlt(p,jday,obs); }
while (jday < jdmax) {
for (i in objects) { p = objects[i]; odat2[p] = PlanetAlt(p, jday+1.0, obs); }
for (i in objects) { // check for events relative to Sun
p = objects[i];
for (var a=0; a<360; a += 90) {
// a = desired difference in longitude, 0 = new Moon/vernal equinox or solar conjunction,
// 90 = 1st quarter/summer solstice/quadrature etc
if (p == SUN) {
dlon0 = rev2(odat0[p][5] - a);
dlon2 = rev2(odat2[p][5] - a);
} else {
dlon0 = rev2(odat0[p][5] - odat0[SUN][5] - a);
dlon2 = rev2(odat2[p][5] - odat2[SUN][5] - a);
}
if (SGN(dlon2)!=SGN(dlon0) && Math.abs(dlon2)<20 && Math.abs(dlon0)<20) {
// the <20 test necessary, otherwise "oppositions" detected as well"
odat1 = PlanetAlt(p,jday+0.5, obs);
sdat1 = PlanetAlt(SUN,jday+0.5, obs);
if (p == SUN) dlon1 = rev2(sdat1[5]-a);
else dlon1 = rev2(odat1[5]-sdat1[5]-a);
var n0 = nzero(dlon0,dlon1,dlon2);
var jdzero = jday + 0.5 + n0/2;
if ((p==MERCURY || p==VENUS) && dlon2<0) // detect if inferior conjunction
l_events[l_events.length] = new Array(jdzero, p, SUN, 2, 0, 0);
else
l_events[l_events.length] = new Array(jdzero, p, SUN, a/90, 0, 0);
}
}
}
if (sel.conj_moon || sel.conj_planet) {
for (i = 1; i < objects.length-1; i++) { // check for mutual conjunctions, Sun ignored
p = objects[i];
for (var j = i+1; j < objects.length; j++) {
var q = objects[j];
dlon2 = rev2(odat2[p][5] - odat2[q][5]);
dlon0 = rev2(odat0[p][5] - odat0[q][5]);
if (SGN(dlon2)!=SGN(dlon0) && Math.abs(dlon2)<20 && Math.abs(dlon0)<20) {
odat1 = PlanetAlt(p,jday+0.5, obs);
sdat1 = PlanetAlt(q,jday+0.5, obs);
dlon1 = rev2(odat1[5] - sdat1[5]);
n0 = nzero(dlon0,dlon1,dlon2);
jdzero = jday + 0.5 + n0/2;
odat1 = PlanetAlt(p, jdzero, obs); sdat1 = PlanetAlt(q, jdzero, obs);
l_events[l_events.length] = new Array(jdzero, p, q, 0, odat1[6]-sdat1[6], 0);
}
}
}
}
for (var i in objects) {p = objects[i]; odat0[p][5] = odat2[p][5];}
jday += 1.0;
}
} // end longitudeEvents()
function elongEvents(obs, jdmax, l_events) {
// Detect max elongations for Mercury, Venus
var e0 = new Array(); var e1 = new Array(); var e2 = new Array();
var jdmin = jd0(obs.year,obs.month,obs.day) + obs.tz/1440.0;
var jday = jdmin;
bodies[MERCURY].elongupdate(jday-1.0,obs); e0[0]=bodies[MERCURY].elong;
bodies[MERCURY].elongupdate(jday,obs); e1[0]=bodies[MERCURY].elong;
bodies[VENUS].elongupdate(jday-1.0,obs); e0[1]=bodies[VENUS].elong;
bodies[VENUS].elongupdate(jday,obs); e1[1]=bodies[VENUS].elong;
while (jday < jdmax+1.0) {
for (var i=0; i<=1; i++) {
var p = (i==0 ? MERCURY : VENUS);
bodies[p].elongupdate(jday+1.0,obs); e2[i]=bodies[p].elong;
if (e1[i]>e0[i] && e1[i]>e2[i]) {
n0 = nextrem(e0[i],e1[i],e2[i]);
jdextr = jday + n0;
if (jdextr>=jdmin && jdextr<=jdmax) {
bodies[p].elongupdate(jdextr,obs);
l_events[l_events.length] = new Array(jdextr, p, p, 4, bodies[p].elong, bodies[p].pa);
}
}
e0[i]=e1[i]; e1[i]=e2[i];
}
jday+=1.0;
}
} // end elongEvents()
function distEvents(obs, jdmax, l_events,sel) {
// Detect peri/aphelion peri/apogee
var e0 = new Array(); var e1 = new Array(); var e2 = new Array();
var jdmin = jd0(obs.year,obs.month,obs.day) + obs.tz/1440.0;
var jday = jdmin;
bodies[SUN].update(jday-1.0,obs); e0[0]=bodies[SUN].dist;
bodies[SUN].update(jday,obs); e1[0]=bodies[SUN].dist;
bodies[MOON].update(jday-1.0,obs); e0[1]=bodies[MOON].dist;
bodies[MOON].update(jday,obs); e1[1]=bodies[MOON].dist;
while (jday < jdmax+1.0) {
for (var i=0; i<=1; i++) {
var p = (i==0 ? SUN : MOON);
bodies[p].update(jday+1.0,obs); e2[i]=bodies[p].dist;
if ((e1[i]>e0[i] && e1[i]>e2[i]) || (e1[i]