[vsnet-alert 10382] Re: checking for new objects in big surveys - usno b1.0 now

[bydra at Safe-mail.net]

-------- Original Message --------
From: Brian Skiff <bas at lowell.edu>

>      Unless I am missing something, doesn't VizieR do all these
> things you describe?  Such as loading lists, searching within limits,
> etc etc.  I do them regularly with VizieR, so I know it's possible!
> And it is, after all, an SQL-based set-up, but just with a much 
> simpler way to set the parameters.

There are (admittedly increasingly rarer) times when vizier just isn't there.  Certain more complex SQL combinations aren't possible, although likely that matters little to the vast majority of people.

VizieR doesn't always work properly, some days it does, some things just do not work.  This may be browser dependent, it's not clear, I don't have access to a wide range of browsers to try.  Some days some things work, others they don't, is also a case.  The other day I was trying to demonstrate to someone how to find a range of RA and Dec in VizieR from the 2XMM catalogue.  It totally ignored the range set, or even a simple greater than option, and gave the lot.  I've used the range setting and conditionals in vizier successfully before, but I've also seen them not work work as well as work, I've never figured out why not.  2XMM is not in GATOR of course, but I've had range settings and conditionals not work in VizieR before.  Radius search stuff fine, but parameter setting sometimes ignored.

Of less import to likely nearly everyone is that VizieR has limits on data return on bulk catalogues that can be quite restrictive in terms of field size. Sometimes it crashes on relatively small datasets, always in the same damn spot, at the server end, sometimes the Strasbourg server takes forever, sometimes the Harvard mirror is incredibly fast, sometimes not.

If vizier is playing up, GATOR is an alternative, a backup.  Otherwise VizieR would indeed always be preferred.

Then again, some days GATOR acts up.

Cheers

John