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Johannesburg Centre,
Astronomical Society of Southern Africa
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Constellations listed with a grey background are never visible from most of South Africa.
About a dozen of the brightest stars are arranged in a distinct cross at the center of this open cluster, whic contains about 100 stars in an area about 20' across.
Neighbour cluster to M38, with a loose central concentration of stars forming a warped cross. A pair of close double stars straddles the cluster centre. It's about 12' in diameter
Small cluster, with vast network of dark lanes, beautiful red star in the centre. A beautiful object even for small telescopes, it has an apparent diameter of 24' into wich more than 500 stars are packed. The brightest stars are about Mv 10; how many you will see depends on the sixe of scope and viewing conditions.
One of the objects easily visible to the naked eye, and thus known since prehistoric times. It contains a peculiar blue star. With a diameter of 95' (three times that of the Moon), binoculars will show dozens of stars.
One of the oldest known open clusters, being aged at ~ 3.2 billion years. It is of a similar age to our Solar System and its stars happen to have a similar chemical composition to the Sun. It is a rich cluster about 28' across, containing about 500 stars, the brightest of which are around Mv 9.
At 40' diameter, it fills an area of the sky 30% larger than the full moon. About 20 stars can be see through binoculars. An excellent target for any scope. In 7x35 binocs, both Sirius and M41 fit in the field of view.
Cluster of faint stars of differing brightness.
With 100 or so stars in a cluster about 1° across, this needs a large field. Contains scattered groups and irregular sprays of stars.
A bright and well condensed cluster. Good resolution is obtained in an 8" telescope.
Eta Carina with its associated star clusters and the great diffuse gaseous nebulae is one of the very finest of telescopic objects. The star, which has exhibited irregular behaviour and which was once the brightest int eh southern skies, is considered to be one of the most likely to go supernova. Teh nebula is about 400 light years across; at 8000 light years distance, it subtends more than 4º and is easily visible to the naked eye.
Numerous bright scattered stars and a number of bright orange stars. With some 150 stars brighter than Mv 12, it is one of the richest and brightest open clusters. Needs a large field.
A huge diffuse nebula, easily visible to the naked eye at the edge of the Large Magellanic Cloud. It is about 800 light years across in general but has filiments extending as much as 1700 light years
Very large and complex wreath-like nebula, surrounding a bright galactic star cluster NGC 2244. This can be observed by binoculars, though does best photographically as it is visually faint. Generally acknowledged to be one of the finest deep-sky objects.
Very large and scattered cluster of ~20 bright stars and over hundred fainter members, surrounded by a vast but faint nebulosity. The cluster, visible in binoculars, extends about 20 light years. From earth, it subtends 26' (about the diameter of the Moon). The stars are embedded in the nebula from which they were born, with the dark Cone nebula (3000 ly distant) superimposed.
An emission nebula. An enormous cloud of fluorescent gas, mainly hydrogen, glowing by the ultraviolet radiation streaming from Theta Orionis, a bright grouping of four massive stars commonly called the Trapezium. Probably the best-known and most observed nebula, it is always beautiful whatever instrument is used. Situated at a distance of about 1600 ly, this stellar nursery is some 30 ly across.
Bright, very large cluster.
[of Argo Navis]
Elaborate mix of bright and faint stars visible to the naked eye. Contains about 50 stars of Mv 6-12 within a 25' circle, with no nebulosity.
A finger-width from M47. Cluster of very faint stars; some 100 stars of Mv 9-13 are packed into a 20' circular area. They are situated at roughly 5400 ly.
A visual treat containing some 300 stars within a 27' circle. Core has a distinct arrowhead shape.
Brilliant 1st-magnitude open cluster. Excellent in binoculars or a small scope. The faint nebulosity is really only apparent in large telescopes or on photographs. How many stars (Pleiads) can you see with the naked eye? 7 or maybe 17? About 100 are accessible to amateur telescopes. It lies at a distance of 7 ly and is about 380 ly across.
Bright open cluster. Good binocular target. About 200 stars are packed into a volume 8 ly across, at a distance of 151 ly.
One of >100 known supernova remnants in our galaxy. Remains of a cataclysmic stellar explosion in A.D.1054 when it shined as bright as Venus in the daytime sky for ~23 days.The nebula is till expanding, currently being about 9x14 ly. At its centre is the original star, now a pulsar with its 1,4-Sun mass condensed to 10km in diameter, rotating at 30 revolutions per second.
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Named by Lacaille after Table Mountain in Cape Town.
