[fitsbits] Keywords "explicitly declared ... long-string"? {External}

[Dubois-Felsmann, Gregory P.]

Dear colleagues,

FITS 4.00, §4.2.1.2 "Continued string (long-string) keywords" contains the statement:

"The CONTINUE keyword must not be used with of [sic] any of the mandatory or reserved keywords defined in this Standard unless explicitly declared of type long-string."

I have looked moderately diligently through the whole of FITS 4..00 as well as https://heasarc.gsfc.nasa.gov/docs/fcg/standard_dict.html and I cannot find an instance of a keyword "declared of type long-string".

Was this sentence included as groundwork for the possible future introduction of keywords declared as long-string?  Or to support projects that wish to declare keywords of their own as long-string?  Or was it intended to actually be used for some particular keyword(s) in the standard, but with that intent withdrawn before 4.00 actually appeared?

This is not a theoretical question; we are working on polishing our standards-compliance in both Rubin and SPHEREx prior to the release of data to users later this year.

Many thanks,
Gregory

--
Gregory Dubois-Felsmann, Ph.D. | Senior Staff Scientist | Caltech/IPAC
Science Platform Scientist, Vera C. Rubin Observatory
Pipeline System Designer, NASA SPHEREx mission
Mail Code MR 100-22 | Pasadena, CA 91125-2200 | gpdf at ipac.caltech.edu