James Dunlop's Catalog of Deepsky Objects
In the years 1823-1827, James Dunlop
(1795-1848) observed the southern skies from the Brisbane observatory at
Paramatta, New South Wales, Australia.
He compiled several catalogs, among them the Brisbane Catalog of over
7000 southern stars, and A Catalogue of Nebulae and Clusters of Stars in
the Southern Hemisphere observed in New South Wales of 629 entries for
deepsky objects [Dunlop (1828)]. However, many of
these objects are badly described, so that John Herschel could only verify 211
of them. New research, led by Glen Cozens, brought up a number of further
"real" objects, so that actually roughly over 300 (or about 50 %) seem to
belong to "real" deepsky objects. The other half is asterisms and multiple
stars which Dunlop's comparatively small instruments (a 9-feet FL, 9-inch
aperture reflector with speculum metal mirror, perhaps equivalent to about a
modern 6-inch reflector) didn't resolve.
Glen Cozens (Cozens 2008,
2010) has identified Dunlop's objects to consist of
128 objects in the Large Magellanic Cloud (LMC),
31 objects in the Small Magellanic Cloud (SMC),
and 187 deepsky objects outside the Magellanic Clouds. Of the latter, there
are 50 galaxies, 78 open clusters, 34 globular clusters, 4 planetary nebulae,
3 nebulae, 12 asterisms and 4 other objects, all together 346 identified
deepsky objects. 37 entries are duplicates, with different positions, for
objects already contained in the catalog. The remaining entries mostly seem
to be faint double or multiple stars.
The most spectacular original discovery of Dunlop is perhaps that of peculiar
radio galaxy NGC 5128 in Centaurus (also called
Centaurus A), his Dunlop 482. Also included in his original discoveries are
Sculptor Group galaxies NGC 55 (Dun 507),
300 (Dun 530), and 7793 (Dun 608), and a considerable number of further
southern galaxies, diffuse nebulae, open clusters, as well as 23 new globular
clusters (plus two independent rediscoveries), 4 diffuse nebulae
(the Wolf-Rayet nebula NGC 3199=Dun 332, starforming nebulae NGC 3324=Dun 322
and NGC 3372=Dun 309 (Lac 3.6, the Eta Carinae Nebula), and the reflection
nebula IC 2966=Dun 266), and 5 planetary nebulae (NGC 2818=Dun 564,
NGC 5189=Dun 252, NGC 5882=Dun 447, NGC 6326=Dun 381, and NGC 6563=Dun 606).
Dunlop has included 7 Messier objects in his list:
M70=Dun 614, and
These are all but one (M7) south of his declination limit of Dec=-30:00 (1826);
perhaps that cluster was too large and scattered for his telescope.
The Dunlop catalog is arranged in the order of increasing declination or
south polar distance, from south to north; objects which are nearest to the
South Celestial Pole come first. This explains the late numbering of the
comparatively northern Messier objects; M83 is (almost) the northernmost
Besides the catalog, Glen Cozens has also studied James Dunlop's observing
notes on a microfiche edition. These contain 13 more identified objects,
identified by a number "mf" (or "Dun mf"). The list contains all of Lacaille's
objects not contained in the catalog (so we know Dunlop has observed them all),
including the Messier Objects
M4=Dun mf 1178,
M7=Dun mf 1088,
M8=Dun mf 1191, and
M22=Dun mf 1195,
plus the faint galaxy NGC 1947 (Dun mf 421) in Dorado.
This endeavor was the second major effort of a deepsky object survey of the
southern skies, after Lacaille's
list of 42, of 1751-1752.
Here we offer the following options related to Dunlop's catalog online:
Parramatta Virtual Observatory<./a>, by David Povey, Parramatta City Council
- James Dunlop, 1828.
A Catalogue of Nebulae and Clusters of Stars in the Southern Hemisphere
observed in New South Wales.
Philosophical Transactions of the Royal Society, Vol. 118, pp. 113-151
- Glen Cozens and Graeme L. White, 2001.
James Dunlop: Messier of the Southern Sky.
Sky & Telescope, Vol. 101, No. 6 (June 2001), pp. 112-116
- Glen Cozens, 2008.
An analysis of the first three catalogues of southern star clusters and
PhD thesis, James Cook University, 2008, 362 + xxi pages (June 2008)
This work, besides Dunlop's catalog, also treats the catalogs of southern
deepsky objects by Lacaille and
- Glen Cozens, Andrew Walsh, and Wayne Orchiston,
James Dunlop's historical catalogue of southern nebulae and clusters.
Journal of Astronomical History and Heritage, Vol. 13, No. 1, pp. 59 - 73
Other Deep Sky catalogs suitable for the
History of the Discovery of the Deepsky Objects
Last Modification: February 19, 2019