re OBJECT keyword

[Helene Dickel]

To: fitsbits at fits.cv.nrao.edu

Topic: re Draft of FITS standard revision 1.2..
	Section 5.4.2.2 Keywords Describing Observations (OBJECT)
   and	Section 5.2.1   Character String 

As Chair of the IAU Commmission 5 Task Group on Designations, I am  
writing in support of some of the recent suggestions regarding the 
FITS OBJECT key word - its length and its use.

Briefly, the purpose of the IAU Task Group on Designations is to
promote clear and unambiguous identification of astronomical objects 
outside the solar system. Much confusion exists with duplicate acronyms 
and shortened designations appearing in the literature which creates 
problems with archiving and retrieval of data.  Improving the situation 
becomes all the more important as source names are searched in the 
Electronic Journals.  

The Task Group on Designations supports inclusion of Don Well's statement
into Section 5.4.2.2 re OBJECT  and that of Bill Pence into Section 5.2.1 
re Character Strings (both statments attached) in the belief that these 
additions will facilitate rather than hinder the creation and use of 
unambiguous designations which these days can require more than 
24 characters e.g. 

   ("first" release Sloan Digital Sky Survey; Pre-registered to IAU Comm.5)
	1SDSS JHHMMSS.ss+DDMMSS.s  
   <http://vizier.u-strasbg.fr/cgi-bin/Dic?/2887107>

We are also in accord with several other submitted comments which I append.

Thank you for your efforts and best wishes,
Helene R. Dickel, Chair IAU TG on Designations
 
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	From Don Wells  <dwells at NRAO.EDU>  April 17 1998 wrote 
	that the text for 5.4.2.2 OBJECT should include the following
	statement (slightly modified by HRD):

"It is recommended that data systems which originate
OBJECT strings (e.g., telescope/instrument data systems) encourage
observers to use strings which conform to the recommendations of the
Designations Task Group of IAU Commission 5 (Astronomical Data) as 
given in "IAU Recommendations for Nomenclature"
<http://cdsweb.u-strasbg.fr/iau-spec.html>."

	Bill Pence <pence at tetra.gsfc.nasa.gov> suggested on May 5 1998
	adding a couple sentences to the end of section 5.2.1 
	(which defines character string keywords) to the effect:

"The maximum allowed length of a keyword string is 68 characters (with
the opening and closing quote characters in columns 11 and 80,
respectively).  Software which reads or writes any character string
keyword should support strings up to this maximum length."

-----------------------------------------------------------------
Other recommendations that the TG on Designation supports are:

	Steve Willner <willner at cfa183.harvard.edu> on May 5 1998
	included the following in regards to allowed "characters"
	in the OBJECT key word strings:

Also, be sure to allow the necessary special characters:  
colons and parentheses at least and preferably slashes and
equal signs as well.

	Arnold Rots arots at xebec.harvard.edu (& William Pence and Nicolaas Kuin)
	wrote on May 11 1998:

I agree that it is absolutely essential that the syntax of OBJECT be
regulated to conform to the Commission 5 guidelines - or at least to
something the name resolvers can be reasonably expected to handle.

For AXAF, we have designated the keyword TITLE to contain the proposal
title, but in principle it could be used for any kind of "junky"
information, like suggested below, at the discretion of the project
that generates the FITS files.

William Pence wrote:
> Nicolaas Kuin wrote:
> 
> >   There is no reason that Keck and Lick could not introduce their own
> > LICK_OBJ for a string like 
> > LICK_OBJ = 'NGC 1234, 400 s, blue filter, 1200 line grating'
> > which then could be put into the header.
> 
> I'd agree that it would be better to invent a new keyword to record the
> user's observation title, (OBSTITLE?) and reserve OBJECT for its
> intended purpose, which is to give the name of the object observed and
> nothing more.