'10 '' Sunrise-Sunset 11 '' mode =1 Automatic 12 mode=0 20 GOSUB 300 21 '' Chandler Arizona Latitude=33N18 Longitude=-111W50 22 B5=33+(18/60) : L5=-1*(111+(50/60)) 23 H=7 25 if mode=1 then goto 50 30 INPUT "Lat, Long (deg)";B5,L5 40 INPUT "Time zone (hrs)";H 50 L5=L5/360: Z0=H/24 60 GOSUB 1170: T=(J-2451545)+F 70 TT=T/36525+1: '' TT = centuries 80 '' from 1900.0 90 GOSUB 410: T=T+Z0 100 '' 110 '' Get Sun''s Position 120 GOSUB 910: A(1)=A5: D(1)=D7 130 T=T+1 140 GOSUB 910: A(2)=A5: D(2)=D7 150 IF A(2)< A(1) THEN A(2)=A(2)+P2 160 Z1=DR*90.833: '' Zenith dist. 170 S=SIN(B5*DR): C=COS(B5*DR) 180 Z=COS(Z1): M8=0: W8=0: PRINT 190 A0=A(1): D0=D(1) 200 DA=A(2)-A(1): DD=D(2)-D(1) 210 FOR C0=0 TO 23 220 P=(C0+1)/24 230 A2=A(1)+P*DA: D2=D(1)+P*DD 240 GOSUB 490 250 A0=A2: D0=D2: V0=V2 260 NEXT 270 GOSUB 820: '' Special msg? 271 if mode!=1 then goto 280 272 PRINT "Latitude ";B5;" Longitude ";L5*360;" TimeZone ";H 273 PRINT "Day/Month/Year ";nd\$ 280 END 290 '' 300 '' Constants 310 DIM A(2),D(2) 320 REM P1=3.14159265: P2=2*P1 320 P1=PI : P2=2*P1 330 DR=P1/180: K1=15*DR*1.0027379 340 S\$="Sunset at " 350 R\$="Sunrise at " 360 M1\$="No sunrise this date" 370 M2\$="No sunset this date" 380 M3\$="Sun down all day" 390 M4\$="Sun up all day" 400 RETURN 410 '' LST at 0h zone time 420 T0=T/36525 430 S=24110.5+8640184.813*T0 440 S=S+86636.6*Z0+86400*L5 450 S=S/86400: S=S-INT(S) 460 T0=S*360*DR 470 RETURN 480 '' 490 '' Test an hour for an event 500 L0=T0+C0*K1: L2=L0+K1 510 H0=L0-A0: H2=L2-A2 520 H1=(H2+H0)/2: '' Hour angle, 530 D1=(D2+D0)/2: '' declination, 540 '' at half hour 550 IF C0>0 THEN 570 560 V0=S*SIN(D0)+C*COS(D0)*COS(H0)-Z 570 V2=S*SIN(D2)+C*COS(D2)*COS(H2)-Z 580 IF SGN(V0)=SGN(V2) THEN 800 590 V1=S*SIN(D1)+C*COS(D1)*COS(H1)-Z 600 A1=2*V2-4*V1+2*V0: B=4*V1-3*V0-V2 610 D8=B*B-4*A1*V0: IF D8<0 THEN 800 620 D8=SQR(D8) 630 IF V0< 0 AND V2> 0 THEN PRINT R\$; 640 IF V0< 0 AND V2 > 0 THEN M8=1 650 IF V0> 0 AND V2< 0 THEN PRINT S\$; 660 IF V0> 0 AND V2< 0 THEN W8=1 670 E=(-B+D8)/(2*A1) 680 IF E> 1 OR E< 0 THEN E=(-B-D8)/(2*A1) 690 T3=C0+E+1/120: '' Round off 700 H3=INT(T3): M3=INT((T3-H3)*60) 710 PRINT USING "##:##";H3;M3; 720 H7=H0+E*(H2-H0) 730 N7=-COS(D1)*SIN(H7) 740 D7=C*SIN(D1)-S*COS(D1)*COS(H7) 750 AZ=ATN(N7/D7)/DR 760 IF D7< 0 THEN AZ=AZ+180 770 IF AZ< 0 THEN AZ=AZ+360 780 IF AZ> 360 THEN AZ=AZ-360 790 PRINT USING ", azimuth ###.#";AZ 800 RETURN 810 '' 820 '' Special-message routine 830 IF M8=0 AND W8=0 THEN 870 840 IF M8=0 THEN PRINT M1\$ 850 IF W8=0 THEN PRINT M2\$ 860 GOTO 890 870 IF V2< 0 THEN PRINT M3\$ 880 IF V2> 0 THEN PRINT M4\$ 890 RETURN 900 '' 910 '' Fundamental arguments 920 '' (Van Flandern & 930 '' Pulkkinen, 1979) 940 L=.779072+.00273790931*T 950 G=.993126+.0027377785*T 960 L=L-INT(L): G=G-INT(G) 970 L=L*P2: G=G*P2 980 V=.39785*SIN(L) 990 V=V-.01000*SIN(L-G) 1000 V=V+.00333*SIN(L+G) 1010 V=V-.00021*TT*SIN(L) 1020 U=1-.03349*COS(G) 1030 U=U-.00014*COS(2*L) 1040 U=U+.00008*COS(L) 1050 W=-.00010-.04129*SIN(2*L) 1060 W=W+.03211*SIN(G) 1070 W=W+.00104*SIN(2*L-G) 1080 W=W-.00035*SIN(2*L+G) 1090 W=W-.00008*TT*SIN(G) 1100 '' 1110 '' Compute Sun''s RA and Dec 1120 S=W/SQR(U-V*V) 1130 A5=L+ATN(S/SQR(1-S*S)) 1140 S=V/SQR(U):D7=ATN(S/SQR(1-S*S)) 1150 R5=1.00021*SQR(U) 1160 RETURN 1165 '' 1170 '' Calendar --> JD 1171 '' Get current Date 1172 nd\$=DATE\$ 1173 '' DATE\$ - returns the current day as string "DD/MM/YYYY" 1174 M=MID\$(nd\$,4,2)+0 1175 Y=MID\$(nd\$,7,4)+0 1176 Day=MID\$(nd\$,1,2)+0 1177 if mode=1 then goto 1190 1180 INPUT "Year, Month, Day";Y,M,Day 1190 G=1: IF Y< 1583 THEN G=0 1200 D1=INT(Day): F=Day-D1-.5 1210 J=-INT(7*(INT((M+9)/12)+Y)/4) 1220 IF G=0 THEN 1260 1230 S=SGN(M-9): A3=ABS(M-9) 1240 J3=INT(Y+S*INT(A3/7)) 1250 J3=-INT((INT(J3/100)+1)*3/4) 1260 J=J+INT(275*M/9)+D1+G*J3 1270 J=J+1721027+2*G+367*Y 1280 IF F>=0 THEN 1300 1290 F=F+1: J=J-1 1300 RETURN 1310 '' 1320 '' This program by Roger W. Sinnott calculates the times of sunrise 1330 '' and sunset on any date, accurate to the minute within several 1340 '' centuries of the present. It correctly describes what happens in the 1350 '' arctic and antarctic regions, where the Sun may not rise or set on 1360 '' a given date. Enter north latitudes positive, west longitudes 1370 '' negative. For the time zone, enter the number of hours west of 1380 '' Greenwich (e.g., 5 for EST, 4 for EDT). The calculation is 1390 '' discussed in Sky & Telescope for August 1994, page 84. '