ASCII table tricks

[Barry M. Schlesinger]

In article <5079np$ae7 at darkstar.ucsc.edu>, sla at umbra.ucolick.org (Steve Allen) writes...
>In article <199608301312.JAA06260 at tetra.gsfc.nasa.gov>,
>William Pence  <pence at tetra.gsfc.nasa.gov> wrote:
>>
>>The FITS Standard does not allow the ASCII newline character or any
>>other ASCII control characters in an ASCII table.  Section 8.1.5 states
>>that "All data in an ASCII tables extension record shall be ASCII text ..."
>>and "ASCII text" is defined to be the ASCII characters hexidecimal 20-7E.
> 
>But wait, playing standards lawyer for a moment I point out that
>section 8.1.5 is about "entries" in the table.
> 
>In section 8.1.3 it states
>  "The table is constructed from a two-dimensional array of ASCII characters."
>which means anything in 7-bit ASCII.

It says that only ASCII characters are allowed, not that all ASCII 
characters are allowed.

> 
>I believe the standard is saying that the data fields themselves may
>only contain printable text, but that portions of the table outside
>the fields may contain other ASCII charcters.
>

The standard says that all data must be ASCII text, not only data in 
fields.

The original Harten et al. tables paper states, "The data records are 
stored as a large character array....All information is stored as 
8-bit printable ASCII characters..."  This language excludes control 
characters.  There is no entry in appendix C to indicate that the 
standard differs from the FITS papers in this regard.  

This question will probably be discussed at the FITS Technical Panel 
meeting next month.

				Barry Schlesinger
				FITS Support Office
				GSFC/ADF