Editing New General Catalogue (section)

==''Revised New General Catalogue''==
[[File:NGC 6543 7662 7009 6826.jpg|thumb|upright=1.2|Four different [[planetary nebula]]e. Clockwise starting from the top left: [[NGC 6543]], [[NGC 7662]], [[NGC 6826]], and [[NGC 7009]].]]
The ''Revised New Catalogue of Nonstellar Astronomical Objects'' (abbreviated as ''RNGC'') was compiled by Sulentic and Tifft in the early 1970s, and was published in 1973, as an update to the NGC.<ref>
{{cite book
 |last1=Sulentic
 |first1=J. W.
 |last2=Tifft
 |first2=W. G.
 |date=1973
 |title=The Revised New Catalogue of Nonstellar Astronomical Objects
 |publisher=[[University of Arizona Press]]
 |isbn=978-0-8165-0421-3
 |bibcode=1973rncn.book.....S
 |url-access=registration
 |url=https://archive.org/details/revisednewgenera0000sule
 }}</ref> The work did not incorporate several previously published corrections to the NGC data (including corrections published by Dreyer himself), and introduced some new errors. For example, the well-known compact galaxy group [[Copeland Septet]] in the Leo constellation appears as non-existent in the RNGC.<ref name="Steinicke2010">
{{cite web |last=Steinicke |first=W. |date=17 January 2012 |title=Revised New General Catalogue and Index Catalogue |url=http://www.klima-luft.de/steinicke/ngcic/rev2000/Explan.htm |access-date=2012-04-22}}</ref><ref name=history/>

Nearly 800 objects are listed as "non-existent" in the RNGC. The designation is applied to objects which are duplicate catalogue entries, those which were not detected in subsequent observations, and a number of objects catalogued as star clusters which in subsequent studies were regarded as coincidental groupings. A 1993 monograph considered the 229 star clusters called non-existent in the RNGC. They had been "misidentified or have not been located since their discovery in the 18th and 19th centuries".<ref>{{cite web|title=Monograph No. 1 - The "Non-Existent" Star Clusters of the RNGC|url=http://www.webbdeepsky.com/nebulae-clusters/mono1|website=Webb Deep-Sky Society|access-date=29 May 2017}}</ref> It found that one of the 229—NGC 1498—was not actually in the sky. Five others were duplicates of other entries, 99 existed "in some form", and the other 124 required additional research to resolve.<ref>{{cite book|last1=Allison|first1=Mark|title=Star Clusters and How to Observe Them|date=4 April 2006|publisher=Springer Science & Business Media|pages=62–63|url=https://books.google.com/books?id=AgkCl1L1G2cC&pg=PA62|access-date=29 May 2017|isbn=9781846281983}}</ref>

As another example, [[reflection nebula]] NGC 2163 in [[Orion (constellation)|Orion]] was classified "non-existent" due to a transcription error by Dreyer. Dreyer corrected his own mistake in the Index Catalogues, but the RNGC preserved the original error, and additionally reversed the sign of the declination, resulting in NGC 2163 being classified as non-existent.<ref>{{cite book|last1=O'Meara|first1=Stephen James|title=Deep Sky Companions: Hidden Treasures|date=12 April 2007|publisher=Cambridge University Press|pages=175–176|url=https://books.google.com/books?id=a6VY0Q1zsJoC&pg=PA176|access-date=30 May 2017|isbn=9781139463737}}</ref>

=== ''Revised New General Catalogue and Index Catalogue'' ===
The ''Revised New General Catalogue and Index Catalogue'' (abbreviated as ''RNGC/IC'') is a compilation made by Wolfgang Steinicke in 2009.<ref name="Steinicke2010" /><ref>
{{cite book |last=Steinicke |first=W. |title=Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer's New General Catalogue |date=2010 |publisher=[[Cambridge University Press]] |isbn=978-0-521-19267-5}}</ref> It is a comprehensive and authoritative treatment of the NGC and IC catalogues.<ref>
{{cite journal |last=Duerbeck |first=H. W. |date=2009 |title=Book Review: Nebel und Sternhaufen - Geschichte ihrer Entdeckung Beobachtung und Katalogisierung (Steinicke) |journal=[[Journal of Astronomical History and Heritage]] |volume=12 |issue=3 |page=255 |doi=10.3724/SP.J.1440-2807.2009.03.10 |bibcode=2009JAHH...12..255D|s2cid=258223761 }}</ref><ref>
{{cite journal |last=Duerbeck |first=H. W. |date=2011 |title=Observing and Cataloguing Nebulae and Star Clusters. From Herschel to Dreyer's New General Catalogue (Steinicke) |journal=[[Journal of Astronomical History and Heritage]] |volume=14 |issue=1 |page=78 |bibcode=2011JAHH...14Q..78D}}</ref> The number of objects with status of "not found" in this catalogue is 301 objects (2.3%). The brightest star in this catalogue is [[NGC 771]] with magnitude of 4.0.<ref name="Steinicke2010"/>