[vsnet-alert 10769] re Nova Car 2008: astrometry - nomad and ucac2

[bydra at Safe-mail.net]

Greg Bolt qualified :- 

"Using both Nomad and UCAC-2 the result was the same as above"

well, basically, at these magnitudes, and with the likely field of view you'll have used, NOMAD == UCAC2, thus the concurrence was inevitable, except possibly if a Tycho2 star sneaked into the field.  The USNO B1.0 stuff and 2MASS stuff wouldn't have weighted it necessarily unless you'd had a dearth of UCAC2 field stars (2MASS would've been included in NOMAD to supplement this dearth, but only when needed).

NOMAD is not a reprocessing, it's a merging of catalogues.

Cheers

John