[Aavso-photometry] FITS Keyword List

[Pedro Pastor]

Hi,

I was doubting to chime into this thread, I had decided not, but this last
message from Dave give the excuse to enter into the discussion (thanks??).

Well, I'm not entering into the "FITS internals" discussion, but the idea
proposed by Dave is quite appropriate and has a name in Computer Science:
XML.

I know maybe this is not the forum to evangelize about XML in Astronomy, we
have VOTable, but to the reach of my knowledge VOTable is a mere "transport"
of FITS to new (XML) syntax. What we need is a re-definition of the "File
Metadata Header" for Astronomy producing a conceptual standard independent
of file formats (like FITS is), technologies (I don't think FITS is UNICODE
compliant, for example), system vendors (implementation) and users
(vocabularies). Once this conceptual design is done, XML is the way to go
for computer implementation. And "a standard" means a global consensus among
stakeholders and a committee (institution) for preserving and maintaining
the "standard" (what seem to be missing with FITS).

I've been discussing this topic with different people and the answer is
always the same: "There are too many FITS files and software tools to move
to something completely different". Well, I don't think this is a
"scientific way of thinking", but accepting the point, there are many
different examples of this kind of problem (and more complex) on several
other fields of knowledge where this seemed to be a "mission impossible", it
have been done. Libraries, for example, and the MARC standard. A decade ago
librarians argued that they would never move from "pure MARC" to some kind
of XML re-definition (one of the oldest standards in the world, they said),
and at present is a fact. "The harder to learn a standar is and the closer
you are to it, the grater the fear to abandom it"

Well, this are my 2 cents, maybe I've been boring you, but it seems like in
Astronomy all "things" evolve at an astronomical speed.

Best regards,

Pedro


-----Mensaje original-----
De: aavso-photometry-bounces at mira.aavso.org
[mailto:aavso-photometry-bounces at mira.aavso.org] En nombre de Dave Lane
Enviado el: sábado, 05 de enero de 2008 0:43
Para: Michael Newberry
CC: aavso-photometry at mira.aavso.org
Asunto: Re: [Aavso-photometry] FITS Keyword List

Michael Newberry wrote:
> Certainly the image could meet the FITS standard, but that does not 
> necessarily mean that some important keywords it might contain can be 
> understood by any other software. For example, it might use NOISE123  
> for the readout noise, or EXPOSE66 for the exposure time, and the 
> image still would pass the test since the verifier would just assume 
> those 2 keywords are private. But you would run into trouble trying to 
> do photometry on the image because the readout noise and exposure time 
> are not in a readily accessible form.
>   
One thing that developers of image processing software could do is to is to
make their software configurable. All that would be needed is settings in
the software that translates the header key names (and formats if
appropriate) from the to-be-processed files to the software's expected key
names. This is not rocket science.

--- Dave
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