🚀 go-pugleaf

In article <1cibc0INNpjq@darkstar.UCSC.EDU>, sla@umbra.ucsc.edu (Steve Allen) writes...
>I am looking through the NOST 100-0.3b standard document trying to be
>very sure about one point:
> 
>    Section 5.3.2.1 specifies that a "character string shall be composed
>    only of ASCII text."
> 
This section is referring to values of header keywords.

>    Section 6.1 specifies that characters shall be 7-bit ASCII
> 

This section refers to data

>These specifications do not preclude the existence of unprintable characters
>(ASCII 0 through 31 and 127) in a character string.  Is it intended that
>unprintable characters be legal?  Are there FITS readers which will be
>confounded by unprintables?
> 

In Section 3, the term ASCII text is defined to mean "ASCII characters
hexadecimal 20-7E" (decimal 32-127) for the NOST standard.  These
characters are the printable ASCII characters.  Section 4.2 states
"The primary HDU and every extension HDU shall consist of an integral
number of header records consisting of ASCII text, which may be
followed by an integral number of data records."  Thus ASCII decimal
0-31,127 are excluded from headers.  The specification for character
data does not restrict the permitted characters.  Specifications for
individual structures may.  For example, for ASCII Tables, 8.1.5 reads
"All data in an ASCII tables extension data record shall be ASCII
text...."  A restriction to printable ASCII characters and 
NULL (decimal and hexadecimal zero) is proposed for binary tables. 

					Barry Schlesinger
					NOST FITS Support Office