Hello Patrick! Thank you, that was what I heard about UCAC3. GSC has indeed a lot of artefacts.
Using both is not adviseable because of duplets being shown in CdC. If anybody is interested, this is the place where I observe the skies with three friends (I am not the owner!), a superb instrument! http://www.harpoint-observatory.com/ Greetings, Michael --- In [email protected], Patrick Chevalley <p...@...> wrote: > > Hi, > > Magnitude of UCAC3 are better than GSC, and better than UCAC2, but far than > perfect. The main goal for UCAC3 is astrometry. > > Considering just the extract for Skychart, not the full dataset: > - 7 time more objects > - much more precise position > - inclusion of proper motion to conserve precision over time > - color indication > - very good completeness, almost no missing star > - almost no fake star, GSC include a lot of scratch, ghost, ... > - much less duplicate, in GSC almost all stars in plate border appear two to > four time. > - many more faint stars near the bright object halo > > Patrick >
