CHARACTER*50 INFILE1,INFILE2,OUTFILE,FILENAME,FILENAME2
	CHARACTER*8 ANSWER
	CHARACTER*1 BLINE(2400),BLINE2(2400)
	INTEGER*2 ILINE(1200),ILINE2(1200),H,K,L,N
	INTEGER*4 IX,IY,I64K,I32K
	LOGICAL EFLG
	CHARACTER DAT*12,TIM*12
C	DATA STRUCTURE:
	EQUIVALENCE (BLINE,ILINE),(BLINE2,ILINE2)
	CHARACTER*12 AQDATE, AQTIME,AQDATE2, AQTIME2
	REAL*4 LAMBDA,DISTANCE,PHI_START,PHI_END
	EQUIVALENCE (LAMBDA,BLINE(77)),(DISTANCE,BLINE(81)),(PHI_START,
     -  BLINE(85)),(PHI_END,BLINE(89)),(AQDATE,BLINE(101)),
     -  (AQTIME,BLINE(113))
	REAL*4 LAMBDA2,DISTANCE2,PHI_START2,PHI_END2
	EQUIVALENCE (LAMBDA2,BLINE2(77)),(DISTANCE2,BLINE2(81)),
     -  (PHI_START2,BLINE2(85)),(PHI_END2,BLINE2(89)),
     -  (AQDATE2,BLINE2(101)),(AQTIME2,BLINE2(113))
	I64K=256*256
	I32K=I64K/2

5	WRITE(6,1100),1
1100	FORMAT(/'$Input filename',I2,' (CR to quit):  ')
	READ(5,1200) INFILE1
1200	FORMAT(A)
	IF (INFILE1(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE1, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 5
        OPEN (UNIT=1,FILE=INFILE1,readonly,STATUS='OLD')
	WRITE(6,1100),2
	READ(5,1200) INFILE2
	IF (INFILE2(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE2, NAME=FILENAME2,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 5
        OPEN (UNIT=2,FILE=INFILE2,readonly,STATUS='OLD')

	  WRITE(6,1600)
1600	  FORMAT('$Output filename:  ')
	  READ(5,1200) OUTFILE
       OPEN (UNIT=3,FILE=OUTFILE,STATUS='NEW',RECL=2400,
     &  CARRIAGECONTROL='NONE',RECORDTYPE='FIXED')

	READ(1,155) (BLINE(II),II=1,2400)
	READ(2,155) (BLINE2(II),II=1,2400)
	CALL  DATE(DAT)
	CALL  TIME(TIM)
	AQDATE2=DAT
	AQTIME2=TIM
C CHECK FILMS ADJACENT, USE PHI_START OF FIRST AND PHI_END OF SECOND.
C	PRESENT VERSION OF MAR SOFTWARE DOESN'T REPORT PHI_START.
C	IF (PHI_END.NE.PHI_START2) STOP'FILMS NOT ADJACENT!'
	PHI_START2=PHI_START
	write(3,155) (BLINE2(II),II=1,2400)
	DO 200 I=1,1200
	READ(1,155) (BLINE(II),II=1,2400)
	READ(2,155) (BLINE2(II),II=1,2400)
155	FORMAT (4096A1)
	DO 190 J=1,1200
	IX=ILINE(J)
	IF (IX.LT.0.) IX=IX+I64K
	IY=ILINE2(J)
	IF (IY.LT.0.) IY=IY+I64K
	IX=(IX+IY)/2
	IF (IX.GE.I32K) IX=IX-I64K
190	ILINE2(J)=IX
200	write(3,155) (BLINE2(II),II=1,2400)
	CLOSE(UNIT=2)
	CLOSE(UNIT=3)
	WRITE(6,*)'DELETE ',FILENAME,' (Y/N)'
	READ(5,1200),ANSWER
	IF (ANSWER(:1).NE.'Y') GOTO 5
C	IF (ANSWER(:1).NE.'Y').AND.(ANSWER(:1).NE.'y') GOTO 5
	write(6,*)'DELETING ',FILENAME
	J=LIB$SPAWN('DEL '//FILENAME)
C		FILENAME RETURNED BY INQUIRE, HAS VERSION #.
	GOTO 5
	END