Catalogue of Deep Dky Objects (RNGC and NGC2000)
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The basic catalogue of deep sky objects
provided with C2A includes: the Messier catalogue, the NGC
catalogue and IC catalogue. This catalogue is constructed partly from
the original "Revised New General Catalogue" which is well
known in the astronomical community. It is supplemented by the NGC2000
catalogue from which, in particular, dimensions of objects are obtained.
Note that the catalogue of deep sky objects thus constituted contains some
imprecisions and approximations, and it is advisable to use instead the Revised
New General Catalogue and Index Catalogue which is also supplied
with the C2A software.
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Messier and NGC Catalogues
The Messier catalogue contains 110 objects to which are attached several pieces of information:
- the type of object: the objects in the catalogue are of seven different kinds:
- galaxy,
- open cluster,
- globular cluster,
- diffuse nebula,
- planetary nebula,
- open cluster + diffuse nebula,
- diffuse nebula + galaxy.
- the name of the constellation in which
the object appears,
- the name of the object in the form M<num>,
- the common name of the object if there is
one,
- the codified object description; depending on the type of object, there may be several descriptors.
The NGC (New General Catalogue)
contains 8191 deep sky objects, to which are attached several pieces of
information:
- the name of the object in the form NGC<num>,
- the type of object which may be:
- galaxy,
- open cluster,
- globular cluster,
- diffuse nebula,
- planetary nebula,
- open cluster + diffuse nebula,
- diffuse nebula + galaxy.
- unknown (the object does not correspond to anything, or is confused with a nearby object),
- the name of the constellation in which
the object appears,
- the codified object description; depending on the type of object, there may be several descriptors.
IC Catalogue
The IC (Index Catalogue) contains 5385 deep sky objects to which are attached several pieces of information:
- the name of the object in the form IC<num>,
- the type of object which may be:
- galaxy,
- open cluster,
- globular cluster,
- diffuse nebula,
- planetary nebula,
- simple star,
- double star,
- triple star,
- the name of the constella tion in which
the object appears,
- the magnitude of the object,
- the size of the object in arc minutes,
- the right ascension for the epoch 2000,
- the declination for the epoch 2000.
Table of Contents