Re: Wiki and SIMBAD

[Stupendous Man <richmond@a188-l009.rit.edu>]

  I wrote:

>>   One way to describe stars which should provide nearly unique
>> identifiers is by position in the sky, as Tom hinted. 
...
>>             JHHMMSS.ss+DDMMSS.s    i.e.  J010335.75+003553.2

  Michael K. replied:

> It kind of confuses me that this would be the IAU suggestion. As others 
> have noted, as we precess the coordinates will change slightly.

  The "J" in front of the position indicates "equinox J2000", 
which is the system in which the current pipeline produces coordinates.
Precession won't invalidate these names.  Proper motion might,
of course, but not for a few decades to centuries.

> Every 
> star TASS sees will already have a designation, if nothing better than 
> GSC. SIMBAD and the like can cross-reference based on any valid 
> designation, so we can use others' technology to create 
> cross-references, I would think. I personally would love to avoid long 
> numeric coordinate-base names in preference to GCVS/NSV/HD/GSC type 
> names, myself, personally speaking.

  Well, I would, too.  But consider this situation: you have found
something peculiar about a star, based on sifting through a database
or set of data files.  All you know right now is its position.
What do you do?

    - go to SIMBAD and look up stars near the coordinates?
          If so, which of the 13 names do you pick?  HD?  GSC?  SAO?

    - use the position to identify the star
      
  If we pick the first method, we need to agree on an ordered
list for the possible catalog designations: i.e., "use the BD number,
if it has one; or, failing that, the HD number; or, failing that,
the SAO number; or, failing that, the GSC number.  Oh, but if it
has a GCVS designation, use that instead."

  It isn't obvious that HD80945 = CD-395432 = GSC07695-04007.
It is somewhat easier to realize that J092132.33-394145.9 may
possibly be the same as J092132.23-394144.7.

  Sigh.

                            Michael