100 REM  PHOTOMETRIC REDUCTION
110 REM
115 PRINT: PRINT
120 PRINT "INPUT OBSERVATIONS:
125 PRINT
130 INPUT "VARIABLE STAR:";V
140 INPUT "SKY NEAR VARIABLE:";S
150 INPUT "COMPARISON STAR:";C
160 INPUT "SKY NEAR C STAR:";CS
165 PRINT
170 INPUT "MAG. OF C STAR:";M
180 V=V-S: C=C-CS
190 MV=2.5*LOG(C/V)/LOG(10)
195 MV=M+MV
200 PRINT: PRINT "RESULTS:"
210 PRINT "VALUE COM STAR: ";C
220 PRINT "VALUE VARIABLE: ";V
230 PRINT "MAG. COM. STAR: ";M
240 PRINT "MAG. VAR. STAR: ";MV
250 PRINT
260 INPUT "ANOTHER (Y, N)";Q$
270 IF Q$="Y" THEN GOTO 100
280 END
290 REM  ------------------------
300 REM  APPEARED IN ASTRONOMICAL
310 REM  COMPUTING, SKY & TELE-
320 REM  SCOPE, FEBRUARY, 1985
330 REM  ------------------------