[iaufwg] [fitsbits] Start of the ''MBFITS" Public Comment Period

[William Pence]

Robert Hanisch wrote:
> On 5/21/07 10:17 AM, "LC's NoSpam Newsreading account"
> <nospam at mi.iasf.cnr.it> wrote:
> 
>> I had a quick glance to the the summary and full specification pdf docs
>> (quicker for the second).
>>
>> My impressions are :
>>
>>  - the summary is too much a summary for the registry
>>  - the full specification instead is too detailed for the registry
>>    (however could be provided as supplementary document)
> 
> I agree with Lucio.  In addition, I don't really feel qualified to critique
> such a detailed and specialized specification.  If it works for this
> facility, then fine.
> 
> This seems less of a convention and more of a keyword dictionary for this
> particular telescope/application.

[Note that this is addressed to the IAUFWG email list, not FITSBITS]

We seem to keep coming back to the question of "what is a convention?", 
and the purpose of the Registry (a similar discussion took place 
regarding the FOREIGN extension convention).  Here is what the Registry 
web page says:

"A FITS convention is defined as a set of related FITS header keywords, 
and optionally, other data structures within FITS tables or FITS images, 
that are to be used for a specific purpose. Because it is often 
inappropriate or impractical to document these conventions in the FITS 
Standard itself, the Registry provides an alternative process for 
documenting conventions for the benefit of future FITS users."

There are only 3 requirements for including a convention in the Registry

1.  it conforms to the FITS standard
2.  the convention is in actual use
3.  the documentation is clear, and concisely defines how the convention 
should be used.

I think this MBFITS convention meets all these requirements.  Some might 
argue that a 60 page description document is not really "concise", but 
we have to be realistic about what documentation we can expect to 
receive; we can't expect people to spend time writing  (and maintaining 
in the future) new documentation simply for the FITS Registry if 
existing documents will suffice.  This is especially true for 
configuration controlled documents like this MBFITS document;  even if 
someone was willing to take the time to write a more concise summary of 
the MBFITS convention, getting approval to release such a document might 
require a lot of time and effort that the project is unwilling to fund.

There are several other conventions in the queue to be considered for 
the Registry in the near future that are somewhat similar to the MBFITS 
convention (e.g., Single Disk FITS, Interferometry Data Interchange 
FITS, and the Optical/IR Interferometry Data Standard format).   All 
these conventions are fairly complex and have relatively long 
description documents.  I can't think of any good reason to exclude 
conventions like this from the registry, and on the contrary,  I think 
it will prove to be beneficial to the FITS community to have all these 
conventions documented in one place in the Registry.

Generally speaking, I believe that a "Big Tent" philosophy of allowing 
practically any FITS usage to be documented in the Registry will be 
better for the FITS community, rather than trying to set up narrow (and 
somewhat arbitrary) definitions of what types of conventions are good 
enough to go into the registry.  Once a significant number of 
conventions have been entered in the Registry, then perhaps we can 
consider defining finer sub-categories of conventions.

Bill
-- 
____________________________________________________________________
Dr. William Pence                       pence at milkyway.gsfc.nasa.gov
NASA/GSFC Code 662       HEASARC        +1-301-286-4599 (voice)
Greenbelt MD 20771                      +1-301-286-1684 (fax)