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  When FITS was originally developed, there was no standard format for the internal representation of floating point data. Only integer formats were allowed in the data array. The scaling scheme using the keywords BZERO and BSCALE was devised in order to make it possible to represent inherently floating point physical values using a data array of integers. The physical value of the data represented by an array member would be derived from equation 3.2. While scaling is no longer required to represent floating point numbers, it remains a useful tool. Representation of unsigned integer quantities is one application.

Be careful when attempting to scale data sets with large dynamic range. If one converts such data to integers and then tries to convert back to floating point, so much precision may be lost that the original data values will be irretrievable.