Is this what you are looking for? ftp://cdsarc.u-strasbg.fr/0/cats
Regards Robin > -----Original Message----- > From: [email protected] [mailto:skychart- > [EMAIL PROTECTED] On Behalf Of G. G. > Sent: 11 July 2007 21:58 > To: [email protected] > Subject: [skychart-discussion] NOMAD catalog (was USNO-A or USNO-B) > > While looking at the list of catalogs at Vizier site, I stumbled into > NOMAD catalog. It looks like the best catalog (currently) for > astrometric and photometric data. I was wondering if in the future > version of CDC an access to this catalog can be added in the "Online > resources". > > Also, does anyone know how to download a catalog from Vizier site? I > looked and looked, but could not figure it out. > > By the way here is the description of NOMAD catalog: > > Description: > The Naval Observatory Merged Astrometric Dataset (NOMAD) > contains astrometric and photometric data for over 1 billion stars > derived from the Hipparcos (I/239), Tycho-2 (I/259), UCAC2 (I/289), > and USNO-B1.0 (I/284) catalogs for astrometry and optical hotometry, > supplemented by 2MASS (II/246) near-infrared photometry. For each > unique star the "best" astrometric and photometric data are chosen > from the source catalogs and merged into a single dataset. A sequence > of priorities is followed and NOMAD contains flags to identify the > source catalogs and gives cross-reference identifications. This > first release of NOMAD is not a compiled catalog; that is, if a star > is identified in more than 1 of the above mentioned catalogs, only > 1 catalog entry is chosen. > Thus the local and global systematic errors of the various > source catalogs will be present in this version of NOMAD. All source > catalogs astrometric data are on the International Celestial > Reference System within the limitations of the source catalogs. > > > --- In [email protected], John Mahony > <[EMAIL PROTECTED]> wrote: > > > > Unfortunately I know almost nothing about photometry. > > > > You can find just about any catalog on Vizier, and convert them for > CdC using > > CdC's catgen utility (see the "tools" section of the CdC download > page, at > > least for v2.x). > > > > -John > > > > > > --- "G. G." <[EMAIL PROTECTED]> wrote: > > > > > John, > > > > > > Thanks for responding. > > > > > > So, which catalogs (accessible through CDC) are photometric > catalogs? > > > Also, if none is, are there good photometric catalogs on-line? > > > > > > Thanks, > > > Gennady > > > > > > --- In [email protected], John Mahony > > > <jmmahony@> wrote: > > > > > > > > These were intended as astrometric catalogs, not photometric. > To > > > quote from > > > > "read.pht", the readme file on the USNO's website for the > > > photometric data in > > > > the USNO-A1.0 catalog: > > > > > > > > ----------------------------------------- > > > > Summary: > > > > > > > > The photometric calibration of USNO-A1.0 is about as poor as > one > > > can > > > > have and still claim that the magnitudes mean something. > > > > ..... > > > > -------------------------------------- > > > > > > > > -John > > > > > > > > > > > > > > > > --- "G. G." <ggleyzer@> wrote: > > > > > > > > > Often, I use catalogs USNO-A and USNO-B to identify faint > stars. > > > > > However, on many occasions these catalogs do not agree. > Often, > > > the > > > > > difference is quite large (1+ magnitudes). Does anyone know > which > > > of > > > > > these catalogs is more accurate? > > > > > > > > > > Thanks, > > > > > Gennady > > > > > > > > > > > > > > > > > > > > > > > > ______________________________________________________________________ > > > ______________ > > > > Never miss an email again! > > > > Yahoo! Toolbar alerts you the instant new Mail arrives. > > > > http://tools.search.yahoo.com/toolbar/features/mail/ > > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > > > ______________________________________________________________________ > ______________Ready for the edge of your seat? > > Check out tonight's top picks on Yahoo! TV. > > http://tv.yahoo.com/ > > > > > > > > Yahoo! Groups Links > > >
