92 REM          SUNSET
93 REM		TRANSLATED TO BASIC-PLUS BY PROJECT DELTA
99 REM
100 REM SUNRISE AND SUNSET COMPUTED FOR ANY STATION
105 REM DATA (DAY,MONTH) MAY BE PUT AT 900+
106 REM END DATA BLOCK WITH PAIR 99,99
110 DATA 317.5,348.5,377.5,408.5,438.5,469.5
120 DATA 499.5,530.5,561.5,591.5,622.5,652.5
130 DATA 6.65028,8.6875,10.5931,12.63,14.6011,16.6383
140 DATA 18.6097,20.6467,22.6836,.655,2.69194,4.66306
160 DATA 108,102,96,90.8333,108,102,96,90.8333
170 DIM J(12),V(8),U(8),S(12),B(2)
172 C=3.14159/180
174 READ J(K9) FOR K9=1 TO 12
180 READ S(K9) FOR K9=1 TO 12
186 FOR K9=1 TO 8
188 READ V(K9)
190 V(K9)=V(K9)*C
192 NEXT K9
193 Z=5
194 L3=39.1849
195 L4=84.329
200 READ D,M
201 IF D<>99 THEN 204
202 GOTO 9999
204 IF D<>9999 THEN213
208 INPUT 'DAY AND MONTH';D,M
210 PRINT
212 PRINT
213 PRINT '     TWILIGHT PHENOMENA FOR WEEK OF ';
216 ON M GOTO 217,219,221,223,225,227,229,231,233,235,237,239
217 PRINT 'JAN';:GOTO240
219 PRINT 'FEB';:GOTO240
221 PRINT 'MAR';:GOTO240
223 PRINT 'APR';:GOTO240
225 PRINT 'MAY';:GOTO240
227 PRINT 'JUN';:GOTO240
229 PRINT 'JUL';:GOTO240
231 PRINT 'AUG';:GOTO240
233 PRINT 'SEP';:GOTO240
235 PRINT 'OCT';:GOTO240
237 PRINT 'NOV';:GOTO240
239 PRINT 'DEC';
240 PRINT D;'TO';D+6
241 PRINT
242 PRINT 'FOR STATION LATITUDE ';L3;'AND LONGITUDE ';L4;'DEGREES'
243 PRINT 'IN TIME ZONE ';Z
245 PRINT
250 PRINT TAB(9);'ASTRONOMICAL  NAUTICAL    CIVIL     ';
260 PRINT 'RISE/SET     AZIMUTH'
300 PRINT TAB(11);'HR   MIN   HR   MIN   HR   MIN   HR   MIN';
310 PRINT '    DEGREES'
1000 DEF FNB(X)=ATN(SQR(1-X^2)/X)
1010 DEF FNA(X)=ATN(X/SQR(1-X^2))
1049 P=3.14159
1052 L1=L3*C
1054 L2=L4*C
1056 S3=236.55/3600*15*C
1060 G=282.442+180
1080 R=.985647
1085 E=1.67213E-02
1090 E2=E^2/2
1115 T=319.679
1132 PRINT 'SUN'
1134 GOSUB 1170
1136 PRINT 'MON'
1138 GOSUB 1170
1140 PRINT 'TUE'
1142 GOSUB 1170
1144 PRINT 'WED'
1146 GOSUB 1170
1148 PRINT 'THUR'
1150 GOSUB 1170
1152 PRINT 'FRI'
1154 GOSUB 1170
1156 PRINT 'SAT'
1158 GOSUB 1170
1160 PRINT:PRINT
1164 READ D,M
1165 IF D<>9999 THEN 201
1166 RESTORE
1167 GOTO 100
1169 REM DETERMINE TIME FOR CHOSEN ZENITH ANGLE
1170 J1=J(M)+D-1
1172 S0=S(M)*15*C+(D-1)*S3
1173 J2=J1
1176 K1=1
1178 GOSUB 4010
1179 R4=A
1180 FOR N=1 TO 8
1190 FOR M1=1 TO 3
1200 C2=-TAN(L1)*TAN(D2)+1/COS(L1)/COS(D2)*COS(V(N))
1202 IF ABS(C2)<1 THEN 1222
1204 U(N)=99
1206 GOTO 1350
1222 IF C2>=0 THEN 1230
1224 H=FNB(C2)+P
1226 GOTO 1240
1230 H=FNB(C2)
1240 IF N>4 THEN 1270
1250 H=-1*ABS(H)
1260 GOTO 1290
1270 H=ABS(H)
1290 S4=H+R4
1300 T3=(S4-S0+L2)/(1+S3/6.28319)
1310 J1=J2+T3/24
1320 GOSUB 4010
1322 R4=A
1330 NEXT M1
1340 U(N)=T3/C/15-42/3600
1350 IF N=4 OR N=8 THEN 1356
1355 GOTO 1450
1356 IF U(N)<>99 THEN 1360
1357 B(K1)=999
1358 GOTO 1395
1360 Y=-COS(D2)*SIN(H)/COS(P/2-V(N))
1370 X=(SIN(D2)*COS(L1)-COS(D2)*COS(H)*SIN(L1))/COS(P/2-V(N))
1380 GOSUB 8000
1390 B(K1)=A/C
1395 K1=K1+1
1450 NEXT N
1455 D=D+1
1465 GOSUB 6000
1470 RETURN
4000 REM SOLVE KEPLER'S EQN
4010 R1=R*(J1-T)*C
4020 E3=R1+E*SIN(R1)+E2*SIN(2*R1)
4030 R2=E3-E*SIN(E3)
4040 D1=(R1-R2)/(1-E*COS(E3))
4050 E3=E3+D1
4060 IF ABS(D1)<=.00001 THEN 4080
4070 GOTO 4030
4080 R3=1-E*COS(E3)
4090 T2=SQR((1+E)/(1-E))*TAN(E3/2)
4100 F=2*ATN(T2)/C
4110 L=G+F+180+.01719*(J1-T)/365.25
4120 IF L<=360 THEN 4160
4130 L=L-360
4140 GOTO 4120
4160 L=L*C
4170 S1=SIN(L)*.397835
4180 D3=SQR(1-S1^2)
4210 D2=FNA(S1)
4220 X=COS(L)/D3
4230 Y=SIN(L)*.917457/D3
4240 GOSUB 8000
4250 RETURN
5000 REM GOSUB FOR UNPACKING
5010 IF W<0 THEN Q8=-1 ELSE IF W=0 THEN Q8=0 ELSE Q8=1
5011 W1=Q8*INT(ABS(W))
5020 W2=ABS(W-W1)*60
5030 W3=INT(W2+.5)
5040 IF W3<60 THEN 5050
5042 W3=0
5044 W1=W1+1
5050 RETURN
6000 PRINT 'MORNING';
6020 K3=1
6025 B1=1
6030 PRINT TAB(10);
6035 FOR K1=K3 TO K3+3
6036 IF U(K1)<> 99 THEN 6040
6037 PRINT '  ********  ';
6038 GOTO 6080
6040 W=U(K1)-Z
6042 IF W>=0 THEN 6046
6044 W=W+24
6045 GOTO 6050
6046 IF W<24 THEN 6050
6048 W=W-24
6050 GOSUB 5000
6060 PRINT USING '##',W1;:PRINT'    ';:PRINT USING '##',W3;:
	PRINT'   ';
6080 NEXT K1
6085 IF B(B1)<>999 THEN  6090
6086 PRINT '*****'
6087 GOTO 6095
6090 PRINT INT((B(B1)+.05)*10)/10
6095 IF K1>=8 THEN 6150
6100 PRINT 'EVENING';
6110 B1=2
6120 K3=5
6130 GOTO 6030
6150 PRINT
6160 RETURN
8000 REM FOUR-QUAD ARCTAN
8020 A=ATN(Y/X)
8030 IF X<0 OR Y<0 THEN 8050
8040 RETURN
8050 IF X>0 AND Y<0 THEN 8080
8060 A=A+P
8070 RETURN
8080 A=A+2*P
8090 RETURN
9000 DATA 19,3,99,99
9988 DATA 9999,9999,9999,9999
9999 END