Celestial Atlas
Non-Traditional Discovery Dates Link for sharing this page on Facebook
Page last updated Jan 24, 2018

 The primary reason for this page is that Wolfgang Steinicke's exhaustive study of William Herschel's published and unpublished papers has created a substantial number of cases in which the traditional dates of discovery (usually based on Herschel's published catalogs of 2500 nebulae and clusters) do not agree with Steinicke's research. In addition, there are a few cases in which Steinicke's currently published database also disagrees with the discovery dates for other objects (primarily those found by John Herschel and James Dunlop), and even some in which my own study of the historical literature (and/or of others working on this topic) have resulted in a change of the "traditional" discovery dates.
 The main content of this page will be a table of NGC/IC objects for which the traditional and actual dates of discovery by William Herschel differ; but there will also be a table of similar cases for other observers.
 This page was created on Jan 15, 2018, and although I consider it an important resource it is not the main objective of my current work, so it will probably take a year or two for it to be more or less complete.

Table Of William Herschel's Discoveries With Altered Discovery Dates
NGC/IC Number
WH ID
Traditional Date
Corrected Date

Table Of Other Objects With Altered Discovery Information
(?? mean this is a suggested change, but is controversial)
NGC/IC Number
NGC 6067
NGC 6087
NGC 6115
NGC 6125 = 6127 = 6128
NGC 6127 = 6125 = 6128
NGC 6128 = 6125 = 6127
NGC 6130
Traditional Information
(May 8) 1826 (Dunlop 360)
(May 8) 1826 (Dunlop 326)
Jul 8, 1834 (J Herschel)
Apr 24, 1789 (W Herschel)
Apr 24, 1789 (W Herschel)
Apr 24, 1789 (W Herschel)
Jul 28, 1886 (L Swift)
"Corrected" Information
May 8, 1826 (Dunlop 360 & 361)
May 8, 1826 (Dunlop 326 & 335)
Jun 26, 1826 (Dunlop)
Jun 28, 1886 (L Swift) ??
Jul 6, 1886 (L Swift) ??
Jun 28, 1886 (L Swift) ??
Apr 24, 1789 (W Herschel) ??
Celestial Atlas
Non-Traditional Discovery Dates