Top 10 Deep-Sky Objects for Stargazers (Southern Hemisphere)

Milky Way galaxy
Image Credit: Babak Tafreshi / Science Photo Library

Dutch-American astronomer Bart Bok once famously stated that “the Southern Hemisphere holds all the good stuff,” and he was right. Counted amongst the riches that belong to the southern celestial sphere are an astonishing array of beautiful deep-sky objects, including the naked-eye galaxies known as the Small and Large Magellanic Clouds; the globular clusters 47 Tucanae and Omega Centauri; the Helix Nebula and Coalsack Nebula; and the Jewel Box open cluster; to name but a few.

Many of these dazzling stargazing objects have been mentioned in two previous “Top 10” posts written about Nebulae and Stars Clusters, which I encourage you to read. For this reason, the 10 items on this list represent a selection of some other objects that can generally not be seen from much above the equator, and while some may not be as well-known as their famous cousins, they are nonetheless stunning to view, and we are sure that some of them will become favorites of northern hemisphere observers from now on, even if they cannot see them directly. So read on and learn more about some of the most awe-inspiring deep-sky objects that can be seen from the Southern Hemisphere.

Wishing Well Cluster (NGC 3532)

Wishing Well Cluster (NGC 3532)
Image Credit: ESO’s La Silla Observatory in Chile

– Constellation: Carina
– Object type: Open cluster
– Coordinates: RA 11h 05m 12s | Dec. -58° 44′ 1″
– Magnitude: +3
– Distance: About 1,321 light years
– Other designations: C 1104-584, Caldwell 91, Melotte 103, Football Cluster, Wishing Well Cluster

Since NGC 3532 was the first deep-sky object to be imaged by the Wide Field and Planetary Camera (WFPC) of the Hubble Space Telescope in May 1990, it is perhaps fitting that our list should start with this pretty open cluster. The cluster contains about 150 stars with magnitudes of about 7 or less, and among the dimmer members are seven red giants, as well as a large number of stars in binary systems. John Herschel, the son of William Herschel, often observed this cluster, and he is said to have admired this collection of stars as being “…among the finest clusters in the sky”. We agree.

Centaurus A

Centaurus A
Image Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

– Constellation: Centaurus
– Object type: Peculiar galaxy
– Coordinates: RA 13h 26m | Dec. – 43° 01′
– Magnitude: +6.84
– Distance: 10 –16 million light years
– Other designations: NGC 5128, Centaurus A, Cen A, Bennett 60

Being the fifth-brightest galaxy in the entire sky, this merger between a large elliptical galaxy, and a smaller spiral galaxy is an easy target for binoculars and small telescopes for southern observers. The core of the galaxy is populated mainly by old, highly evolved stars, while the superimposed dust lane that encircles the galaxy contains more than one hundred known starburst regions.

The image above is a composite of optical, radio, and x-ray frequencies that shows the two high-powered jets of radiation in x-ray frequencies extending above and below the galaxy for several thousand light years, moving at 50% of the sped of light. It is thought the galaxy also contains a super massive black hole, with a mass of about 55 million Suns.

Sculptor Galaxy (NGC 253)

Sculptor Galaxy (NGC 253)– Constellation: Sculptor
– Object type: Intermediate spiral galaxy
– Coordinates: RA 00h 47m 33s | Dec. -25° 17′ 18″
– Magnitude: +8
-Distance: 11.4 million light years
– Other designations: Silver Coin Galaxy, Silver Dollar Galaxy, NGC 253, UGCA 13, PGC 2789 Caldwell 65

Visible in binoculars close to the star Beta Ceti, this intermediate spiral galaxy is among the biggest galaxies known, and as such, it ranks alongside the Andromeda galaxy in terms of visibility. While binoculars easily reveal the Sculptor Galaxy, telescopes with apertures of 400mm and more will reveal the dust lane that extends northwest of the nucleus, as well as a dozen or more faint stars scattered across the galactic bulge. NGC 253 is also known for the several super star clusters it contains. One such cluster has a mass of around 1.4 × 107 and contains a large number of super-massive and luminous Wolf-Rayet stars. Another, slightly smaller, and less massive cluster has a mass of at least 1.5 × 106 Suns, and shines with an absolute magnitude of -15.

Carina Nebula (NGC 3372)

Carina Nebula (NGC 3372)
Image Credit: Harel Boren

– Constellation: Carina
– Object type: Emission nebula
– Coordinates: RA 10h 45m 08.5s, | Dec. -59° 52′ 04″
– Magnitude: +1.0
– Distance: 6,500-10 000 light years
– Other designations: NGC 3372, ESO 128-EN013, GC 2197, Caldwell 92

Located within the Carina–Sagittarius Arm of the Milky Way galaxy, this large combination of dark and bright luminosity is one of the largest such structures known, being about four times bigger (and several times brighter) than the better-known Orion Nebula. In terms of complexity, there is nothing in the northern hemisphere to compete with this nebula.

The Carina Nebula contains multiple, discrete open clusters; as well as the massive Carina OB1 Association that encompasses the star clusters Trumpler 14 (the youngest star cluster known at only 500,000 years old), and Trumpler 16, which contains WR 25, the brightest known star in the Milky Way. The Carina Nebula also surrounds the supergiant star Eta Carinae, which is an incredible four million times brighter than our sun, and up to 150 times more massive. Furthermore, the Carina Nebula contains the open clusters Trumpler 15, Collinder 228, Collinder 232, NGC 3324, and NGC 3293 as members of the Carina OB1 Association. As a matter of interest, the young cluster Trumpler 14 is the furthest removed from the oldest cluster NGC 3293, which indicates that most, if not all of the Carina Nebula is one vast star-forming region.

Homunculus Nebula

Homunculus Nebula
Image credit: Jon Morse, University of Colorado / NASA

– Constellation: Carina
– Object type: Emission nebula
– Coordinates: RA 10h 45m 03.591s, | Dec. -59° 41′ 04.26″
– Magnitude: Variable from -1.0 to +7.6
– Distance: 7,500 light years
– Other designations: 231 G Carinae, HR 4210, HD 93308, CD-59°2620, IRAS 10431-5925, GC 14799, AAVSO 1041–59

The Homunculus Nebula in arguably the most conspicuous object in the Carina Nebula. It is also one of the most unstable objects known, and its luminosity can vary from it being almost the brightest object in the sky, to fading to well below naked-eye visibility in less than 100 years.

The heart of the Eta Carinae phenomenon is made up of two stars that orbit each other once every 5.54 years, and although the components cannot be observed directly, long observation coupled with some intricate calculations have revealed the primary star to be a luminous blue variable star, with a mass of around 150 to 250 Suns. However, this star, which incidentally is the only known star to emit ultraviolet laser radiation, is estimated to have lost about 30% of its mass already, and is fully expected to self-destruct in a massive supernova explosion in the near future, astronomically speaking, of course.

Tau Canis Majoris Cluster (NGC 2362)

NGC 2362
Image Credit: NASA’s Spitzer Space Telescope

– Constellation: Canis Major
– Object type: Open cluster
– Coordinates: RA 07h 18.8m 00s | Dec. -24° 57′ 00″
– Magnitude: +4.1
– Distance: 4,800 light years
– Other designations: Caldwell 64

This little cluster may not be the biggest open cluster visible from the southern hemisphere, but it certainly is among the prettiest. NGC 2362 has a mass of about 500 Suns,  and is closely related to the giant nebula Sh2-310 behind it, and out of which the cluster is thought to have formed about 4 to 5 million years ago.

Eight-Burst Nebula (NGC 3132)

Eight-Burst Nebula (NGC 3132)– Constellation: Vela
– Object type: Planetary nebula
– Coordinates: RA 10h 07m 01.76s | Dec. -40° 26′ 11″
– Magnitude: +9.87
– Distance: 2,000 light years
– Other designations: Southern Ring Nebula, Caldwell 74

The protrusions, or bubbles-upon-bubbles around the outer fringes of this planetary nebula are the result of the multiple outbursts of the central, progenitor star that is now making the gas envelope fluoresce due to its 100,000K temperature. Although this image shows an inner star, this star is in fact one of two stars in what appears to be a close binary system.

Blue Planetary Nebula (NGC 3918)

Blue Planetary Nebula (NGC 3918)
Image Credit: ESA/Hubble and NASA

– Constellation: Centaurus
– Object type: Planetary nebula
– Coordinates: RA 11h 50m 17.7s | Dec. -57° 10′ 56.9″
– Magnitude: +8.5
– Distance: 4,900 light years
– Other designations: The Southerner, He2-74, Hen 2-74, Sa2-81, PK 294+4.1, PN G294.6+04.7, ESO 170-1

Not only is NGC 3918 the brightest of the planetary nebula visible from the far south, it is also among the most stunning nebulae in the entire sky. Easily visible, even with modest amateur equipment, observers are able to see the beautiful blue coloration, which is somewhat reminiscent of the snapshots Voyager 2 took of Neptune in 1989. Although this image reveals the hot remains of the central progenitor star, this star is normally not visible in optical frequencies simply because its light is absorbed by the much brighter gas envelope around it. Note that while the nebula is expanding at about 24 km per second, it is also approaching us at the rate of about 20 km per second.

Southern Pinwheel Galaxy (M83)

Southern Pinwheel Galaxy (M83)
Image Credit: Salvatore Grasso

– Constellation: Hydra
– Object type: Spiral galaxy
– Coordinates: RA 13h 37m 00.9s | Dec. -29° 51′ 57″
– Magnitude: +7.54
– Distance: 15.21 million light years
– Other designations: NGC 5236, UGCA 366, PGC 48082, Southern Pinwheel Galaxy

Being among the closest and most luminous galaxies to us, the Southern Pinwheel is a simple binocular target, while even small to medium telescopes will easily reveal some spiral structure. Strangely though, it was only during 2008 that a concerted effort by NASA revealed the bright pink knots on the fringes of the galaxy to be active star forming regions, which was at first thought not to be possible. This is because these regions were believed to contain no material suitable for star formation to take place, and certainly not star formation at the high rate that has since been observed.

Milky Way

Milky Way
Image Credit: Tanya Schmitz

Views of the Milky Way are not created equal, as this image clearly shows. This particular short exposure image of the Milky Way, that shows the centre of the galaxy towards the lower left, was taken over the town of Sutherland in South Africa, which houses the South African Large Telescope (SALT) and a collection of other South African, and internationally owned and operated telescopes collectively known as the South African Astronomical Observatory (SAAO). Note the Large Magellanic Cloud near the bottom right edge of the frame. Given this view, it is perhaps not surprising that a large part of the Square Kilometre Array radio telescope is to be situated near this location.

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