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<p class="MsoNormal">Hi Gregory,<o:p></o:p></p>
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<p class="MsoNormal">As folks can infer from my ancient comments, I’m leery of relying on such fiddly features, and I also had nothing to do with whatever wording of either CONTINUE or “type long-string” in the FITS standard.<o:p></o:p></p>
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<p class="MsoNormal">What I’m wondering is whether Rubin or SPHEREx are really using CONTINUE – specifically, that is, with mandatory or reserved keywords. What is the use case?<o:p></o:p></p>
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<p class="MsoNormal">Or are you rather wondering if you need to support type long-string in general? Note that it is perfectly legal FITS to define a bintable extension to contain all metadata that in antediluvian days would have shown up in ASCII header keywords.
One can leave the structural FITS headers for the mandatory keywords and a short list of others like CHECKSUM and avoid using awkward conventions or data types entirely.<o:p></o:p></p>
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<p class="MsoNormal">That said, if you are worrying about writing documentation explaining your FITS usage, Rubin software and data must be quite mature at this point.<o:p></o:p></p>
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<p class="MsoNormal">Rob<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">On 2/25/25, 12:04 AM, "fitsbits" wrote:<o:p></o:p></p>
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External Email<br>
<br>
Dear colleagues,<br>
<br>
FITS 4.00, §<a href="http://4.2.1.2"><font color="red"><b>MailScanner warning: numerical links are often malicious:</b></font> 4.2.1.2</a> "Continued string (long-string) keywords" contains the statement:<br>
<br>
"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."<br>
<br>
I have looked moderately diligently through the whole of FITS 4..00 as well as <a href="https://heasarc.gsfc.nasa.gov/docs/fcg/standard_dict.html">
https://heasarc.gsfc.nasa.gov/docs/fcg/standard_dict.html</a> and I cannot find an instance of a keyword "declared of type long-string".<br>
<br>
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?<br>
<br>
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.<br>
<br>
Many thanks,<br>
Gregory<br>
<br>
--<br>
Gregory Dubois-Felsmann, Ph.D. | Senior Staff Scientist | Caltech/IPAC<br>
Science Platform Scientist, Vera C. Rubin Observatory<br>
Pipeline System Designer, NASA SPHEREx mission<br>
Mail Code MR 100-22 | Pasadena, CA 91125-2200 | gpdf@ipac.caltech.edu<br>
<br>
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