DOUBLE PRECISION (REAL(KIND=8) or REAL*8)

  A DOUBLE PRECISION constant has more than twice the accuracy of a
  REAL number, and greater range.

  A DOUBLE PRECISION constant occupies eight bytes of memory.  The
  number of digits that precede the exponent is unlimited, but
  typically only the leftmost 15 digits are significant.

  Either VAX D_floating, G_floating, or IEEE T_floating format is
  used, depending on the compiler option specified.