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Re: (IAAC) Revised NGC / IC



Hello all,
while an appreciated compilation in many respect, Wolfgang's revngc (and
probably revic ) basically improves positions and identifications. I find
a number of outdated/erroneous data in magnitudes and classifications, for
whatever I'm looking, e.g. the planetary nebulae magnitudes appear to be
the same photographic magnitudes that are in the Sky Catalogue 2000.0
(which differ highly from the visual mag's just for these objects), as is
e.g. the classification for NGC 5866 which is wrongly given as "E6/P"
while it should be S0_3 or S0/Sa or such (again, either from Becvar or
Sky Catalogue 2000.0). You should be aware of this when using this
appreciated database.
For galaxies, it seems to me that NED has rather consistent data, but
still I'm not totally satisfied with all their magnitudes (anyway, I can't
seem to see which band they represent). Similar with the SIMBAD data. For
Planetary Nebulae, I prefer Hynes. In general, Uranomatria DSFG seems to
be not so bad. Only for the Messier objects and a small number of others,
I've tried to compile and hold updated data within the Messier pages. For
the Messiers only, there is Don Machholz' consistent estimate (also within
the Messier pages, from his Messier Marathon book). Best, certainly, for
globulars with William E. Harris' list (see
http://www.seds.org/messier/xtra/supp/mw_gc.html ). Worst still for
diffuse nebulae, for many of which there are apparently no estimates at
all.
Clear skies,
  Hartmut Frommert <spider@seds.org, http://www.seds.org/~spider/>
    Maintainer of the Messier pages at SEDS:  http://www.seds.org/messier/
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