R CrA Nebula NGC 6729 + Globular Cluster NGC 6723

R CrA Nebula
R CrA Nebula: Galactic cloud, globular cluster (NGC 6723) and reflection nebula (NGC 6726, 6727 and 6729, IC 4812); Takahashi FSQ-106ED bei f/5.0; SBIG STL-11000M; Astro-Physics 1200GTO; 35x5 min; Namibia, Tivoli Southern Sky Guest Farm, 1360 m ASL; © 31. 5. 2011 Manuel Jung [45]


The globular cluster NGC 6723 was discovered on 2 June 1826 by the Scottish astronomer James Dunlop using the self-built 9-inch reflector at Parramatta observatory near Sydney, Australia. Based on six observations he listed it as number 573 and summarized his description as follows: «A beautiful bright round nebula, about 3.5' diameter, moderately and gradually condensed to the centre. This is resolvable. The moderate condensation, and the bluish colour of the stars which compose it, give it a very soft and pleasant appearance. This is rather difficult to resolve, although the condensation is not very great.» [50]

In October 1860 German astronomer Julius Schmidt observed this area using the 6.2-inch Plössl refractor at the Athens Observatory and discovered the two bright reflection nebulae NGC 6726 and NGC 6727 around the stars TY CrA and HD 176386. On 15 June 1861 he discovered another nebula (NGC 6729) around star TY CrA. [364]

Nebula IC 4812 surrounding the two stars HD 176269/176270 was discovered on 4 August 1899 by American astronomer DeLisle Stewart. He worked at Harvard's Arequipa station in Peru and used the 24" f/5.6 Bruce photographic refractor. [277, 364]

Physical Properties

The nebulae belong to Corona Australis Molecular Cloud and a star-forming region. The involved star R CrA is a variable Herbig Ae/Be at a distance of 128 pc. [145] Globular cluster NGC 6723 is much farther away: 8.7 kpc. [251]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Name RA Dec Type bMag vMag B-V SB Dim PA z D(z) MD Dreyer Description Identification, Remarks
NGC 6723 18 59 33.2 -36 37 52 GCL (VII) 6.8 13 8.700 globular, vL, vlE, vgbM, rrr, st 14…16 GCL 106, ESO 396-SC10
NGC 6726 19 01 39.2 -36 53 29 RN 9 × 7 0.140 * 6·7 in F, pL, neb ESO 396-N13, pair with N 6727
NGC 6727 19 01 42.2 -36 52 35 RN 80 0.140 * 8 in F, pL neb ESO 396-N14, pair with N 6726
NGC 6729 19 01 55.3 -36 57 28 EN+RN 25 × 20 1.300 Var * (11…) with neb!! ESO 396-N*15
IC 4812 19 01 03.5 -37 03 37 RN+* 10 × 7 0.130 * 7 inv in eL neb ESO 396-*N12, CED 165A

Finder Chart

The nebula complex with NGC 6729 and globular cluster NGC 6723 are located in the constellation Corona Australis, south of the teapot in Sagittarius. At a declination of roughly -37° they reach in Switzerland only about 5° above the southern horizon from end of July to beginning of August and are mostly blocked either by the Swiss Alps or the lightpollution dome of Milano. Maybe one can see it on a clear, dry night from the top of a mountain while whole Italy has a power outage.

Finder Chart R CrA Nebula NGC 6729 + Globular Cluster NGC 6723
R CrA Nebula NGC 6729 + Globular Cluster NGC 6723 in constellation Corona Australis. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

More Objects Nearby (±15°)


  • [45] Astro-, Landschafts- und Reisefotografie sowie Teleskopbau, Manuel Jung; sternklar.ch
  • [50] «VIII. A catalogue of nebulæ and clusters of stars in the southern hemisphere, observed at Paramatta in New South Wales, by James Dunlop, Esq. In a letter addressed to Sir Thomas Makdougall Brisbane, Bart. K. C. B. late Governor of New South Wales. Presented to the Royal Society by John Frederick William Herschel, Esq. Vice President» James Dunlop;Philosophical Transactions of the Royal Society of London, Volume 118, pages 113-151, published 1 January 1828; DOI:10.1098/rstl.1828.0010
  • [145] SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
  • [149] SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
  • [160] The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
  • [251] «Young Radio Pulsars in Galactic Globular Clusters» Jason Boyles, Duncan R. Lorimer, Phil J. Turk, Robert Mnatsakanov, Ryan S. Lynch, Scott M. Ransom, Paulo C. Freire, Khris Belczynski; The Astrophysical Journal, Volume 742, Number 1; DOI:10.1088/0004-637X/742/1/51
  • [277] «Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
  • [364] Steve Gottlieb's NGC Notes; astronomy-mall.com/Adventures.In.Deep.Space/steve.ngc.htm