Celestia Forums

Ok...as part of my project, I've been using Simbad rather extensively these past few months.

In the course of this, I have noticed a number of problems with the various Simbad entries. Mostly, these are things like missing ID numbers (HD, DM, and even Tycho), but also includes what I think of as 'False Mirrors' for a given star: said star will have two or more entries, but one such will be nearly void of data and the other will have the 'real stuff'.

It is almost like the compilers of Simbad were working from incomplete general catalogue lists when they put the site together.

By now, my list of 'problem entries' is probably into the three digit range (havn't done an exact count). So...do the folks at Simbad (who-ever they are) accept corrections of this sort? If so, how to go about getting hold of them? I thought about jumping right in, but figured I'd ask you guys first. (figure Fridger and Starguy, at least would have some experience with this).

So...do the folks at Simbad (who-ever they are) accept corrections of this sort? If so, how to go about getting hold of them?

Most definitely yes.

http://simbad.u-strasbg.fr/guide/ch02.htx

The relevant quote:

The data contained in SIMBAD are also permanently updated, as a result of errata, remarks from the librarians (during the scanning of the literature), quality controls, or special efforts from the CDS team to better cover some specific domains (e.g., multiwavelength emitters and complex objects). Requests for corrections, errata, or suggestions are regularly received from SIMBAD users through a dedicated e-mail address (question(at)simbad.u-strasbg.fr).

Corrections of errors are made under the responsibility of CDS astronomers coordinated by G?rard Jasniewicz. All the remarks received from the users are very welcome, as they help us to improve the database contents through the scrutiny of specialists' eyes.

You may want to send an email to ask them the best way to send in a thousand corrections, though. Expect some resistance (after all, they need to make sure your new information is better than what's already in the system)

[It is almost like the compilers of Simbad were working from incomplete general catalogue lists when they put the site together

They probably were. The digital version of the HD catalog on Vizier seems to date back to 1985 (for instance); SIMBAD is older than that(!). I admit a lot of these things could be corrected by importing the contents of the Vizier catalog (note: Vizier is also run by CDS Strasbourg, presumably because they realized a compendium of catalogs was needed) but to do that for EVERY catalog and spot all the slightly different coordinates is a monumental task.

but also includes what I think of as 'False Mirrors' for a given star: said star will have two or more entries, but one such will be nearly void of data and the other will have the 'real stuff'.

And then there are catalogs with information that's just plain wrong, either by accident, lack of precision (either they're old, or in some wavelength like X-rays where we can't/couldn't resolve objects down to arcsecond precision), or some philosophical difference (the Gliese catalog gives the same positions for both components if they're separated by only a few arcseconds; the USNO-B catalog includes a lot of false entries they didn't want to filter out automatically, for fear of removing real things). High proper motion objects are especially bad- give an inaccurate proper motion in a paper, or the wrong epoch or equinox of observation, AND a new name, and CDS Strasbourg will think it's a different star at a slightly different location.