The circumpolar - sub-circumpolar Southern Sky
The southern skies in Australia are glorious for virtually the entire year... a sky that the poor North Americans never to get to see...
Let's start with what's visible just after dark, from mid-January through September:
Use the Southern Cross [Crux] and the two "pointers" [Alpha and Beta Cantaurus, named Rigel Kentaurus and Hadar, resp.] as your guides.
These stars and constellations are visible for most of the year from southern latitudes, but of course their relative position in the sky changes from hour to hour, and month to month...
This part of the sky contains a very rich region of the Milky Way, a variety of beautiful deep sky objects (many accessible to the naked eye or binoculars), and ready access to the Large Magellanic Cloud [LMC] and Small Magellanic Cloud [SMC].
Let's start with Alpha Centauri (also known as Rigel Kantaurus). It is the third brightest star in the sky, and in fact is a "double star" resolved easily through a small telescope. Its near neighbour, Proxima Centauri, is the closest star to our solar system (excepting the sun, of course).
The Southern Cross is towards the upper left, and the pointers are towards bottom centre.
Moving up to the Southern Cross, a 3 inch (75 mm) or larger telescope also resolves Alpha Crucis to be a double star:
(or, with star atlas orientation)
[Remember that the genitive case of a constellation's name is used in conjunction with an individual star's name -- thus Alpha Crucis, not Alpha Crux.]
A short distance from Beta Crucis is the Jewel Box open cluster (NGC 4755), a splendid object in a small telescope:
[RA 12 h 56.3 m, Dec -60 deg 20', Mag 4.2]
It can be seen with binoculars but is observed better with a small telescope:
It looks like this in a large telescope / time exposure:
Another nice open star cluster, NGC 3766, is only a few degrees away:
[RA 11 h 36.1 m, Dec -61 deg 37', Mag 5.3]
It too is visible in binoculars:
but is better in a small telescope:
The most spectacular globular star cluster in the sky is only a short distance away (Omega Centauri, NGC 5139):
[RA 13 h 26.8 m, Dec -47 deg 29', Mag 3.6]
It is visible to the naked eye, better in binoculars:
and better again in a small telescope:
[Note: Due to northern hemisphere bias in many products, these two images are not photos of Omega Centauri, but rather of the VERY SIMILAR M13 globular cluster in Hercules.]
It looks like this in a large telescope / time exposure:
If you are away from city lights, use your eyes alone, and then binoculars, to scan the Milky Way, from the Southern Cross northwards -- it is quite spectacular...
At the edge of the Southern Cross itself, look for the Coal Sack, an area of dark nebulae that blocks out the light from the stars behind it...
Moving now to the west - northwest, we come to the bright portion of the Milky Way (which was shown above) in Carina and Centaurus.
Let's start with Theta Carinae (IC 2602, also known as the "Southern Pleiades), which is both a double star and in fact a star cluster:
[RA 10 h 42.3 m, Dec -64 deg 24', Mag 2.7]
It is quite pretty even in binoculars:
Five degrees away lies the Eta Carinae Nebulae (NGC 3372 [NS 285]) -- a small red "blob" in binoculars or a small telescope, but resolved in larger telescopes (see map above):
[RA 10 h 45.1m, Dec -59 deg 41', Mag 6]
In a small telescope, it looks like this:
A time exposure from the Digitized Sky Survey shows the extent of the nebulosity (click here: 333 KB).
And closer still:
A large number of interesting star fields lie in this part of the sky -- a good "explore" with binoculars is most worthwhile... In particular, I recommend:
NGC 3532, a HUGE open cluster of magnitude 3 and angular size of nearly one degree: 11h 6m, -58.6 deg
NGC 3293, another large open cluster of magnitude 4.8 and angular size of 1/2 degree: 10h 36m, -58.2 deg
Let's now move to the two Clouds of Magellan, the Large Magellanic Cloud [LMC] and Small Magellanic Cloud [SMC]. Because they are on the opposite side of the south celestial pole to the Southern Cross, they appear to "set" as the Cross "rises". Thus:
the LMC is best observed immediately after dark from November through early May; and
the SMC is best observed immediately after dark from September through early March.
Large Magellanic Cloud through time exposure:
Small Magellanic Cloud through time exposure:
Both the LMC and the SMC are separate "satellite" galaxies to our own. The LMC is about 160,000 light years away and contains about 20 billion stars; the SMC is somewhat more distant and somewhat smaller.
They are best explored with the naked eye and then by binoculars.
There are also some interesting objects within and/or aligned with both...
The Large and Small Magellanic Clouds: Two irregular "satellite" galaxies
Large Magellanic Cloud:
The Tarantula Nebulae (NGC 2070) lies near the eastern end of the LMC. It is (just) visible to the naked eye, quite a feat, given that it's located in another galaxy! It is more than 1000 light years across, some 30 times the size of the Orion Nebulae. [In fact, if it were as close as the Orion Nebulae, it would fill the entire constellation of Orion!]
[RA 5 h 38.6m, Dec -69 deg 5', Mag 8]
A small fuzzy patch in binoculars, a small telescope shows more:
In a large telescope / time exposure:
Henize 44, an emission nebula in the LMC [RA
5 h 21.6m, Dec -67 deg 56 min]
The Henize 55 star forming region in the LMC [RA 5 h 32.2 m, Dec -67 deg 40 min]
Small Magellanic Cloud:
Again, it is best explored with binoculars or a wide angle (low power) telescope. The globular star cluster 47 Tuscanae (NGC 104) lies near the edge of the SMC (by optical alignment only -- it is much closer than the SMC and is part of our own Milky Way galaxy).
[RA 0 h 24.1 m, Dec -72 deg 5', Mag 4]
It is visible to the naked eye, better in binoculars:
while a very large telescope shows the detail:
Written by Stephen R. Kessell
Updated 17 January, 2001
