function ut(h,m,z)
{ return (h-z+m/60); }

function jd(y,m,d,u)
{ return (367*y)-Math.floor((7/4)*(Math.floor((m+9)/12)+y))+Math.floor(275*m/9)+d-730531.5+(u/24) }

function frm(n)
{ return Math.round(n*1000)/1000 }

function azimuth(lg,la,ye,mo,da,ho,mi,zo)
{ with (Math) {
var uu=ut(ho,mi,zo);
var jj=jd(ye,mo,da,uu);
var T=jj/36525;
var k=PI/180.0;
var M=357.5291+35999.0503*T-0.0001559*T*T-0.00000045*T*T*T
M=M % 360
var Lo=280.46645+36000.76983*T+0.0003032*T*T
Lo=Lo % 360
var DL=(1.9146-0.004817*T-0.000014*T*T)*sin(k*M)+(0.019993-0.000101*T)*sin(k*2*M)+0.00029*sin(k*3*M)
var L=Lo+DL
var eps=23.43999-0.013*T
var delta=(1/k)*asin(sin(L*k)*sin(eps*k))
var RA=(1/k)*atan2(cos(eps*k)*sin(L*k),cos(L*k))
RA=(RA+360) % 360
var GMST=280.46061837+360.98564736629*jj+0.000387933*T*T-T*T*T/38710000
GMST=(GMST+360) % 360
var LMST=GMST+lg
var H=LMST-RA
var eqt=(Lo-RA)*4
var azm=(1/k)*atan2(-sin(H*k),cos(la*k)*tan(delta*k)-sin(la*k)*cos(H*k))
azm=(azm+360) % 360

return azm
}}

function altitude(lg,la,ye,mo,da,ho,mi,zo)
{with (Math) {
var uu=ut(ho,mi,zo);
var jj=jd(ye,mo,da,uu);
var T=jj/36525;
var k=PI/180.0;
var M=357.5291+35999.0503*T-0.0001559*T*T-0.00000045*T*T*T
M=M % 360
var Lo=280.46645+36000.76983*T+0.0003032*T*T
Lo=Lo % 360
var DL=(1.9146-0.004817*T-0.000014*T*T)*sin(k*M)+(0.019993-0.000101*T)*sin(k*2*M)+0.00029*sin(k*3*M)
L=Lo+DL
var eps=23.43999-0.013*T
var delta=(1/k)*asin(sin(L*k)*sin(eps*k))
var RA=(1/k)*atan2(cos(eps*k)*sin(L*k),cos(L*k))
RA=(RA+360) % 360
var GMST=280.46061837+360.98564736629*jj+0.000387933*T*T-T*T*T/38710000
GMST=(GMST+360) % 360
var LMST=GMST+lg
var H=LMST-RA
var eqt=(Lo-RA)*4
var alt=(1/k)*asin(sin(la*k)*sin(delta*k)+cos(la*k)*cos(delta*k)*cos(H*k))
return alt;
}}

function settoday()
{ 
 setuserday();
}
function setuserday()
{
 thisyear=document.getElementById("Year").value;
 thismonth=document.getElementById("Month").value;
 thisday=document.getElementById("Day").value;
 thishour=document.getElementById("Hour").value;
 thisminute=document.getElementById("Minute").value;
 thiszone=document.getElementById("Zone").value/3600;
}


function sunpos()
{
var lg=1.0*35;
var lgmi=1.0*22;
var la=1.0*45;
var lami=1.0*2;
var ye=1.0*thisyear;
var mo=1.0*thismonth;
var da=1.0*thisday;
var ho=1.0*thishour;
var mi=1.0*thisminute;
var zo=1.0*2;
var twr=1.0*(-7);
var ewv="East";
var nsv="North";

var k=Math.PI/180.0;
lg=lg+lgmi/60
la=la+lami/60
lgo=lg
lao=la
aa=180.0

if (ewv=="East") { ewvr="Восточной долготы" } else { ewvr="Западной долготы" }
if (nsv=="North") { nsvr="Северной широты" } else { ewvr="Южной широты" }
if (ewv=="West") { lg=-1.0*lg }
if (nsv=="South") { la=-1.0*la; aa=0.0 }

var alt=altitude(lg,la,ye,mo,da,ho,mi,zo)
var azm=azimuth(lg,la,ye,mo,da,ho,mi,zo)

h1=0
m=0
alt1=altitude(lg,la,ye,mo,da,h1,m,zo)
azm1=azimuth(lg,la,ye,mo,da,h1,m,zo)
s=-0.8333

// find midday interval
for (var h=0; h<24; h++){
h2=h
azm2=azimuth(lg,la,ye,mo,da,h2,m,zo)
if ((azm1<=180)&&(azm2>=180)){
ha1=h1
ha2=h2
}
h1=h2
azm1=azm2
}
// find exact midday time
mino=1.0;
for (h=ha1; h<ha2; h++){
for (m=0; m<60; m++){
azmo=azimuth(lg,la,ye,mo,da,h,m,zo)
dfo=Math.abs(aa-azmo)
if (dfo<=mino) {
mino=dfo
hno=h
mno=m
}}}
mday=""

altnoon=altitude(lg,la,ye,mo,da,hno,mno,zo);
if (altnoon<s){ mday="nigth" }

hr="не происходят"
mr=""
hs="не происходят"
ms=""
htwr="не происходят"
mtwr=""
htws="не происходят"
mtws=""

mintwr=0.1;
minr=0.1

for (h=0; h<=hno; h++){
for (m=0; m<60; m++){
if (60*h+m< 60*hno+mno){
altr=altitude(lg,la,ye,mo,da,h,m,zo)

dftwr=Math.abs(twr-altr)
if (dftwr<=mintwr) {
mintwr=dftwr
htwr=h
mtwr=m
}

if (altnoon > s){
dfr=Math.abs(s-altr)
if (dfr<=minr) {
minr=dfr
hr=h
mr=m
}}}}}

mins=0.1;
mintws=0.1;

for (h=hno; h<24; h++){
for (m=0; m<60; m++){
if (60*h+m >= 60*hno+mno){
alts=altitude(lg,la,ye,mo,da,h,m,zo)

if(altnoon>s){
dfs=Math.abs(s-alts)
if (dfs<=mins) {
mins=dfs
hs=h
ms=m
}}

dftws=Math.abs(twr-alts)
if (dftws<=mintws) {
mintws=dftws
htws=h
mtws=m
}}}}



cikti="";
if (mo<=9)
 cikti="";
else
 cikti="";
cikti="";




cikti=cikti+"Сумерки утренние: "+htwr+":"+mtwr+" ";
cikti=cikti+"Восход: "+hr+":"+mr+" ";
cikti=cikti+"Сумерки вечерние:"+htws+":"+mtws+" ";
cikti=cikti+"Заход: "+hs+":"+ms+" ";

hourback("header_big",htwr,mtwr,hr,mr,htws,mtws,hs,ms);

}