AAO image reference UKS 37a. « Previous || Next »
Top left is NE. Image width is 3 degrees
Image and text © 2001-2002, Anglo-Australian Observatory. Photograph from UK Schmidt plates by David Malin.
Corona Australis (the southern crown, CrA) is in the far southern sky but visible from the southern states of the USA. The constellation is small but distinctive. The conspicuous globular cluster NGC 6723 is at the western (right) edge of the photograph, but it is in Sagittarius, and is about 30,000 light years distant.
Our picture is about 3 degrees across and the faint Corona Australis nebula meanders along the Sgr-CrA border nebula in the same E-W direction. Almost all the nebulosity here is starlight, reflected from minute grains of dust, some of which gather into darker condensations ('molecular clouds'), blotting out the background stars. Fainter features can be seen here.
By far the largest and densest of the molecular clouds is at the western (left) end of the picture It is about a degree long, corresponding to eight light years at the 500ly distance of the nebula and is extremely opaque -- background stars are dimmed by an astonishing 35 magnitudes. However, not all is darkness, and the dusty cloud appears to be tipped by a pair of bright stars, embedded in bright reflection nebulae. The brightest of these is NGC 6726-27 and it contains both a visual binary and a variable star. Other wispy nebulae in the western part of the dark cloud betray the presence of young, hidden stars.
NGC objects in this photograph listed in NGC 2000.0 (R.W. Sinnott, Ed.) © Sky Publishing Corporation, 1988:
NGC 6723 Gb 18 59.6 -36 38 s Sgr 11.0 7.3 glob. cl. , vL, vlE, vgbM, rrr, st 14...16 IC 4812 Nb 19 01.1 -37 04 d CrA *7 inv in eL neb NGC 6726 Nb 19 01.7 -36 53 s CrA 2. *6-7 in F, pL, neb NGC 6727 Nb 19 01.8 -36 54 r CrA *8 in F, pL neb NGC 6729 Nb 19 01.9 -36 57 s CrA 1. var* (11...) with neb!!
Related images
AAT 73. The reflection nebula NGC 6726-27
AAT 106. The globular cluster NGC 6723
UKS 37. The tail of the CrA reflection nebula
For details of object position and photographic exposure, search technical table by UKS reference number.