7.2. THE ASCII TABLE EXTENSION

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The numeric value of the table field is then the value of the numeric string multi-

plied by ten (10) to the power of the exponent string, i.e., value = numeric string ×

10(exponent string). The default exponent is zero and a blank field has value zero. There

is no difference between the F, D, and E formats; the content of the string determines its

interpretation. Numbers requiring more precision and/or range than the local computer

can support may be represented. It is good form to specify a D format in TFORMn for

a column of an ASCII table when that column will contain numbers that cannot be

accurately represented in 32-bit IEEE binary format (see Appendix E).

FITS Standard