FUNCTION eckccf5(rt, success)
c------------------------------------------------------------------------
c Calling parameters
c
c  Input:
      REAL*8 rt
c  Output:
      REAL*8 eckccf5
      LOGICAL success

c========================================================================
c ECKCCF5
c
c  Calculates the cloud correction factor of Tom Eck, assuming a constant
c  5% surface reflectivity.
c
c  The only parameter is the TOMS reflectivity (as fraction, not percent)
c
c------------------------------------------------------------------------
c idiot-check rt
c
      IF (rt .LT. 0. .OR. rt .gt. 1.) GOTO 901

      IF (rt .LT. 0.5) THEN
        eckccf5= (1. - 0.05*rt)/0.9
      ELSE
        eckccf5= (1. - rt)
      ENDIF

      success=.TRUE.
      RETURN

c-----------------------------------------------------------------------
c Handle error condition.
c
  901 WRITE(6,91) rt
      success=.FALSE.
      RETURN

   91 FORMAT(' !!! eckccf5: calling parameter rt=',f12.2,
     &       ' out of range.'/
     &       '       value must be in [0,1]')
 
      END