Caldwell catalogue

Caldwell catalogue
Montage of Caldwell Catalogue objects.
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The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore as a complement to the Messier catalogue.[1]

While the Messier catalogue is used by amateur astronomers as a list of deep-sky objects for observation, Moore noted that Messier's list was not compiled for that purpose and excluded many of the sky's brightest deep-sky objects,[1] such as the Hyades, the Double Cluster (NGC 869 and NGC 884), and the Sculptor Galaxy (NGC 253). The Messier catalogue was actually compiled as a list of known objects that might be confused with comets. Moore also observed that since Messier compiled his list from observations in Paris, it did not include bright deep-sky objects visible in the Southern Hemisphere, such as Omega Centauri, Centaurus A, the Jewel Box, and 47 Tucanae.[1][2] Moore compiled a list of 109 objects to match the commonly accepted number of Messier objects (he excluded M110[3]), and the list was published in Sky & Telescope in December 1995.[3]

Moore used his other surname – Caldwell – to name the list, since the initial of "Moore" is already used for the Messier catalogue.[1][4] Entries in the catalogue are designated with a "C" and the catalogue number (1 to 109).

Unlike objects in the Messier catalogue, which are listed roughly in the order of discovery by Messier and his colleagues,[5] the Caldwell catalogue is ordered by declination, with C1 being the most northerly and C109 being the most southerly,[1] although two objects (NGC 4244 and the Hyades) are listed out of sequence.[1] Other errors in the original list have since been corrected: it incorrectly identified the S Norma Cluster (NGC 6087) as NGC 6067 and incorrectly labelled the Lambda Centauri Cluster (IC 2944) as the Gamma Centauri Cluster.[1]

  1. ^ a b c d e f g O'Meara, Stephen James (2002). The Caldwell Objects. Cambridge University Press. ISBN 978-0-521-82796-6.
  2. ^ "Caldwell Club Introduction". Retrieved 2006-09-08.
  3. ^ a b Moore, Patrick (December 1995). "Beyond Messier: The Caldwell Catalogue". Sky & Telescope. 90 (6): 38. Bibcode:1995S&T....90...38M. Archived from the original on 2009-01-16. Retrieved 2024-06-11.
  4. ^ Mobberley, Martin (2009). The Caldwell Objects and How to Observe Them. Springer. ISBN 978-1-4419-0325-9.
  5. ^ Jones, Kenneth Glyn (1991). "Introduction". Messier's Nebulae & Star Clusters. Cambridge University Press. pp. 1–8. ISBN 0-521-37079-5.