Simbad Is A Handy Tool

Simbad really looks useful. For a year or two, I've fantasized about
resorting Messier and NCG, the older catalogs of deep sky objects. They
should first be sorted into groups of different objects - galaxies,
globular clusters, nebulae and open clusters. Then they should be sorted
into descending order of "ease of viewing." This last parameter would be a
(rough) surface integral of relative magnitude, which is the average
surface magnitude of the object times it's angular area. Then amateurs
could just run down the list in descending order of ease of viewing.

In the case of Messier, sorting by object type is easy, but I don't know
exactly what objects NGC contains, nor how many. However, to sort by ease
of viewing, you'd need those two parameters I named above. Does any such
data exist, and if not, could I generate it from existing tables, without
using telescope time? And could I use Simbad to generate position tables
vs. object type?

Have you tried RTGUI from http://www.rtgui.com/, it can be scripted to give
all sorts of outputs.
jc

Hi John,

John Schutkeker wrote:
Simbad really looks useful. For a year or two, I've fantasized about
resorting Messier and NCG, the older catalogs of deep sky objects. They
should first be sorted into groups of different objects - galaxies,
globular clusters, nebulae and open clusters. Then they should be sorted
into descending order of "ease of viewing." This last parameter would be a
(rough) surface integral of relative magnitude, which is the average
surface magnitude of the object times it's angular area. Then amateurs
could just run down the list in descending order of ease of viewing.

In the case of Messier, sorting by object type is easy, but I don't know
exactly what objects NGC contains, nor how many. However, to sort by ease
of viewing, you'd need those two parameters I named above. Does any such
data exist, and if not, could I generate it from existing tables, without
using telescope time? And could I use Simbad to generate position tables
vs. object type?

Try the Deep Sky Browser at http://www.messier45.com

You can query objects by magnitude and type, and limit results to ranges
of RA and declination. For instance, the query "gc gx mag10 dec-30
dec40" will return a list of the globular clusters and galaxies with
magnitude brighter than 10 and at declinations between -30° and +40°.
Similarly, the query "ngc pn mag15 dec0" will return a list of
planetary nebulae in the NGC with magnitude brighter than 15 in the
northern celestial hemisphere. The list also contains the size,
coordinates, and corresponding page numbers in Uranometria, MSA and
SkyAtlas. There are many other options, such as limiting searches to
particular catalogs.

Best Regards,
John.