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 
<[EMAIL PROTECTED]> 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." <[EMAIL PROTECTED]> 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
> 
> 
> 
>  
> 
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