The Discoverers of Southern Deep Sky Objects
(South of declination -20 with galaxies to magnitude 13)
Astronomers have all heard of the Messier catalogue, he listed more than 100 deep sky objects from Paris because they were not the comets he was looking for. But who discovered the southern star clusters, nebulae and galaxies? There are many marvellous objects in the southern sky, the Magellan Cloud galaxies (LMC and SMC), the middle of our Milky Way galaxy, the best globular clusters (47 Tucanae and omega Centauri), the eta Carinae and Tarantula nebulae, the Helix planetary nebula and several impressive star clusters. Ancient aboriginal Australians in WA thought that the LMC was an old man’s camp and the SMC an old woman’s camp.
In 1677 Englishman Edmond Halley (1656-1742), observing from St Helena Island in the South Atlantic, found that the “star” omega Centauri was actually a nebula. It turned out to be a globular cluster. He also made the first catalogue of southern stars.
(341 stars from Latitude, Longitude -15.962, -5.699)
Map
https://goo.gl/maps/6qNxpqAQRRB3E6dh7
The Frenchman Nicolas-Louis de Lacaille (1713-1762) made a small catalogue of non-stellar objects between 23/8/1751 and 18/7/1752 from Strand Street, Cape Town with a 0.5” aperture and other telescopes. Seventeen of these were new open clusters. He also found 4 new globular clusters, 2 nebulae (NGCs 2070 and 3372) and the spiral galaxy Messier 83. He made a large and accurate catalogue of 9,776 southern stars during this time and created 14 new southern constellations. (His observatory was at Lat, Long -33.9216, 18.4231)
Map
https://goo.gl/maps/gY6W4NSrHaemyrxWA
The Scotsman James Dunlop (1793-1848) observed from his backyard at 91 Marsden St. Parramatta, NSW (25 km west of Sydney) with a homemade telescope. His 9 foot long 9” (23cm) aperture speculum mirror (66% copper and 33% tin) telescope was equivalent to a modern 6” Newtonian. In just 7 months, from 27/4/1826 to 24/11/1826, he discovered 155 new open clusters, 50 galaxies, 40 nebulae, 28 globular clusters and 4 planetary nebulae. Dunlop was the first to catalogue the clusters and nebulae in the Magellan Clouds. Unfortunately he also included many faint double stars in his catalogue because he thought, with his poor telescope, that they were small nebulae. Prior to this Christian Carl Ludwig Rümker (1788-1862) and James Dunlop made a catalogue of 7,385 southern stars at the NSW governor Sir Thomas Brisbane’s observatory in Parramatta. (His house was at Lat, Long -33.8141, 151.0027).
Map
https://goo.gl/maps/Gr5rZuC2sXUzoe58A
Sir William Herschel (1738-1822) discovered the planet Uranus in 1781 and 2,400 deep sky objects from England. His son Sir John Herschel (1792-1871) observed objects south of declination -20 from Slough, UK and Feldhausen (11 km SE of Cape Town) between 1/7/1826 and 22/1/1838 using an 18.5” (47cm) aperture speculum mirror in a 20 foot long tube. It was equivalent to a modern 16.5” telescope because, although speculum reflects less light than aluminium, there was no secondary mirror to dim the light. Unlike Dunlop, John Herschel was well educated, rich and well equipped. He found 591 new galaxies brighter than magnitude 13, 253 open clusters, 35 nebulae, 17 planetary nebulae and 11 globular clusters south of declination minus 20 degrees. In four years (8/3/1834-22/1/1838) he catalogued a total of 1137 new clusters, nebulae and galaxies plus 2102 double stars from the Cape. An obelisk at the Grove Primary School marks the site of his telescope.
(Lat, Long -33.98298, 18.46033) Map.
https://goo.gl/maps/Wza7SeKWZnShKXBV9
Harvard College (in Boston, Massachusetts, USA) set up a southern observatory in 1890 and in 1898 installed the Bruce 24” (61cm) refractor astrograph at Arequipa in Peru, 1010 km south of Lima. DeLisle Stewart (1870-1941) and Royal Harwood Frost (1879-1950) used it to photograph the southern sky. A set of plates were made using exposures of four hours.
(Lat, Long -16.3689, -71.5381). Map
https://goo.gl/maps/inAk1yLeEfLsAZyN6
Dr Stewart found 127 new galaxies brighter than magnitude 13, 7 open clusters, 6 globular clusters, 3 nebulae and 1 bright planetary nebulae (IC4406) in 3 years from 14/10/1898 to 3/10/1901, south of declination minus 20 degrees.
Mr Frost found 15 new galaxies brighter than magnitude 13, 3 nebulae and 1 planetary nebulae (IC4599) between 19/6/1903 and 31/8/1904 south of declination minus 20 degrees.
Williamina Fleming (1857-1911) used spectra to discover 13 southern planetary nebulae on plates taken with the Bache 8” telescope at Arequipa between 1893 and 1907. “The Bache telescope … used an objective prism to photograph the spectra of all stars to about the eighth magnitude.” (Popular Science Monthly 1903-04)
Many observers in the northern hemisphere, including William Herschel, Lewis Swift and Edward Emerson Barnard, also found deep sky objects south of declination minus 20, but they were not able to see the far southern sky from the UK and the USA.
William Herschel (1738-1822) discovered 82 galaxies brighter than mag 13 and 41 other objects between declinations -20d and -32d 49m from Slough near London.
Lewis Swift (1820-1913) discovered 108 galaxies brighter than mag 13 between declinations -20d and -45d 36m mostly from Echo Mountain north of Los Angeles.
American Edward Emerson Barnard (1857-1923) discovered 15 galaxies brighter than mag 13 and 10 nebulae between declinations -20d and -40d 27m.
Charles Messier (1730-1817) found 9 globular clusters south of declination -20 from Paris.
When someone finds a comet it is named after them. Unfortunately the discoverers of deep sky objects are largely forgotten. Lacaille, Dunlop, John Herschel, Fleming, Stewart and Frost discovered the wonders of the southern deep sky.
