sunrise.js

function init() {
 today= new Date()
 ID=today.getDate()
 IM=today.getMonth()+1
 IY=today.getYear()+1900
 B5=54.58
 L5=52.14
 H=-3
 P1=3.14159265
 P2=2.*P1
 DR=P1/180.
 document.suncalc.ID.value=ID
 document.suncalc.IM.value=IM
 document.suncalc.IY.value=IY
 document.suncalc.B5.value=B5
 document.suncalc.L5.value=L5
 document.suncalc.H.value=H
 document.suncalc.SR.value=""
 document.suncalc.SS.value=""
}

function myint(x){
 if (x>=0)
 x=Math.floor(x)

 else
 x=Math.ceil(x)
 return x
}

function sunrise(form) {
 with (Math){
 ID=parseInt(form.ID.value)
 IM=parseInt(form.IM.value)
 IY=parseInt(form.IY.value)
 B5=parseFloat(form.B5.value)
 L5=parseFloat(form.L5.value)
 H =parseInt(form.H.value)
 form.SR.value=""
 form.SS.value=""
 L5=L5/360.
 Z0=H/24.

 G=1
 J3=0
 if (IY<1583){
 G=0
 }
 with(Math){
 D1=myint(ID)
 F=ID-D1-.5
 J=-myint(7*(myint((IM+9)/12)+IY)/4)
 if (G != 0) {
 S=((IM-9)<0?-1:1)
 A=abs(IM-9)
 J3=myint(IY+S*myint(A/7))
 J3=-myint((myint(J3/100)+1)*3/4)
 }

 J=J+myint(275*IM/9)+D1+G*J3
 J=J+1721027+2*G+367*IY
 if (F<0) {
 F=F+1
 J=J-1
 }
 }

 T=(J-2451545.)+F
 TT=T/36525.+1.
 T0=T/36525.
 S=24110.5+8640184.813*T0
 S=S+86636.6*Z0+86400.*L5
 S=S/86400.
 SM=myint(S)
 S=S-myint(S)
 T0=S*360.*DR
 T=T+Z0
// funarg 1
 L=.779072+.00273790931*T
 G=.993126+.0027377785*T
 L=L-myint(L)
 G=G-myint(G)
 L=L*P2
 G=G*P2
 V=.39785*sin(L)
 V=V-.01000*sin(L-G)
 V=V+.00333*sin(L+G)
 V=V-.00021*TT*sin(L)
 U=1-.03349*cos(G)
 U=U-.00014*cos(2*L)
 U=U+.00008*cos(L)
 W=-.00010-.04129*sin(2*L)
 W=W+.03211*sin(G)
 W=W+.00104*sin(2*L-G)
 W=W-.00035*sin(2*L+G)
 W=W-.00008*TT*sin(G)
 S=W/sqrt(U-V*V)
 AA1=L+atan(S/sqrt(1-S*S))
 S=V/sqrt(U)
 DA1=atan(S/sqrt(1-S*S))
 R5=1.00021*sqrt(U)
 T=T+1

// funarg 2
 L=.779072+.00273790931*T
 G=.993126+.0027377785*T
 L=L-myint(L)
 G=G-myint(G)
 L=L*P2
 G=G*P2
 V=.39785*sin(L)
 V=V-.01000*sin(L-G)
 V=V+.00333*sin(L+G)
 V=V-.00021*TT*sin(L)
 U=1-.03349*cos(G)
 U=U-.00014*cos(2*L)
 U=U+.00008*cos(L)
 W=-.00010-.04129*sin(2*L)
 W=W+.03211*sin(G)
 W=W+.00104*sin(2*L-G)
 W=W-.00035*sin(2*L+G)
 W=W-.00008*TT*sin(G)
 S=W/sqrt(U-V*V)
 AA2=L+atan(S/sqrt(1-S*S))
 S=V/sqrt(U)
 DA2=atan(S/sqrt(1-S*S))
 R5=1.00021*sqrt(U)
 if (AA2 < AA1) {
 AA2=AA2+P2
 }

 Z1=DR*(90.833)

 S=sin(B5*DR)
 C=cos(B5*DR)
 Z=cos(Z1)
 M8=0.
 W8=0.
 A0=AA1
 D0=DA1
 DA=AA2-AA1
 DD=DA2-DA1
 for(C0=0;C0<=23;C0++){
 P=(C0+1.)/24.
 A2=AA1+P*DA
 D2=DA1+P*DD
 K1=15.*DR*1.0027379
 L0=T0+C0*K1
 L2=L0+K1
 H0=L0-A0
 H2=L2-A2
 H1=(H2+H0)/2.
 D1=(D2+D0)/2.
 if (C0<=0.) {
 V0=S*sin(D0)+C*cos(D0)*cos(H0)-Z
 }
 V2=S*sin(D2)+C*cos(D2)*cos(H2)-Z

 if ((V0<0?-1:1)==(V2<0?-1:1)) {
// return
 A0=A2
 D0=D2
 V0=V2

 continue
 }
 V1=S*sin(D1)+C*cos(D1)*cos(H1)-Z
 A=2.*V2-4.*V1+2.*V0
 B=4.*V1-3.*V0-V2
 D=B*B-4.*A*V0
 if (D<0) {
// return
 A0=A2
 D0=D2
 V0=V2
 continue
 }
 D=sqrt(D)
 EE=(-B+D)/(2.*A)
 if (EE>1 || EE<0.) {
 EE=(-B-D)/(2.*A)
 }
 T3=C0+EE+1./120.
 H3=myint(T3)
 M3=myint((T3-H3)*60.)
 if (V0<0. && V2>0.) {
 form.SR.value=H3+":"+(M3<10?"0":"")+M3
 M8=1.
 }
 if (V0>0. && V2<0.) {
 form.SS.value=H3+":"+(M3<10?"0":"")+M3
 W8=1.
 }
 H7=H0+EE*(H2-H0)
 N7=-cos(D1)*sin(H7)
 D7=C*sin(D1)-S*cos(D1)*cos(H7)
 AZ=atan(N7/D7)/DR
 if (D7<0.) {
 AZ=AZ+180.
 }
 if (AZ<0.) {
 AZ=AZ+360.
 }
 if (AZ>360) {
 AZ=AZ-360.
 }

 A0=A2
 D0=D2
 V0=V2

 }


 if (M8+W8==0) {
 if (V2<0) {
 form.SR.value="Полярная ночь"
 }
 if (V2>0) {
 form.SR.value="Полярный день"
 }
 }
 if (M8+W8!=0) {
 if (M8==0) {
 form.SR.value="Сегодня нет восхода"
 }
 if (W8==0) {
 form.SS.value="Сегодня нет заката"
 }
 }


 }
}