> If needed, this 9-digit star ID number should be given in connection with
> the IAU sanctioned acronym of this project and this data
> release number, such as "3UCAC100200300". The star ID number runs from
> 000000001 to 100766420. Leading zeros are to be used to fill
> 9 digits in the star name.
> I find no reference in the README to the 3UCAC NNN-XXXXXXX format. I may
> have just
> missed it.
> Note also that the largest number given on the SIMBAD page (N=100765502)
> does not
> agree with the largest number given in the README (N = 100766420).
> You're right: it truly is a source of confusion.
Well, the acronym seems to be 3UCAC. The format seems to be different
though, but I would follow what's stated in the SIMBAD dictionary of
> Bill J Gray of projectpluto.com writes at:
> for his most recent Guide8 "in-testing" update:
>>> UCAC-3 numbering modified: UCAC-3 has rapidly passed from its original
>>> designation scheme to an alternative, and a new, final scheme has been
>>> settled upon.
Originally, UCAC-3 stars all had numbers ranging from 1 to slightly over 100
million, giving each star a sequential number with no gaps. Then VizieR
chose the MPOS number, which runs from 1 to slightly over 140 million, with
many gaps. The final decision, made by USNO, was that a UCAC-3 identifier
consists of '3UC' followed by a three-digit zone identifier running from 1
to 360, a dash, and six digits. Thus, '3UC314-159265' would be the 159265th
star in zone 314.
Guide will now show the correct identifier for all UCAC-3 stars, both when
shown from the original data files and from VizieR downloads.
Also, if you have the UCAC-3 data on your hard drive, you can use Go To...
Object name and enter (for example) "3UC314-159265", and Guide will find the
Also, the 'more info' section is more informative, with some UCAC-3 specific
glossary definitions. <<<
I knew it would be s ource of confussion.
So we have a lot of names said to be official in their own way.
I would still use the one given in the Dictionary of Nomenclature but maybe
someone with more authority can guide us.
If we are not to trust the Dictionary as a guide, then where should we look