Deep-sky imaging targets for the southern hemisphere

This page has been on the site since 2006. It has been rewritten for today's cameras and software, but the targets are the same ones that have rewarded southern imagers for decades.

The southern sky holds some of the finest deep-sky objects anywhere, and several of them never rise for observers in Europe or most of North America. From New Zealand they pass high overhead, which means less atmosphere to shoot through.

Eight showpiece targets

Orion Nebula (M42). A bright star-forming cloud in Orion's sword, which from here hangs above the three belt stars as part of "The Pot". It is bright enough for a 200 mm lens and a few seconds of exposure, and it rewards long stacks with a vast surrounding glow.

Eta Carinae Nebula (NGC 3372). Larger and brighter than M42, centred on the unstable giant star Eta Carinae. The dark Keyhole near the core shows well in small refractors. It sits in the rich Milky Way of Carina, so wide fields are full of stars.

Omega Centauri (NGC 5139). The largest globular cluster in our galaxy, several million stars in a ball as wide as the full Moon. Short exposures keep the core from burning out.

47 Tucanae (NGC 104). The second-finest globular, next to the Small Magellanic Cloud. It has a strikingly bright, compact core and is circumpolar from most of the country.

Tarantula Nebula (NGC 2070). A huge star-forming region in the Large Magellanic Cloud, about 160,000 light years away. Its looping filaments show in a modest refractor, and a telephoto shot of the whole LMC places it in context.

Centaurus A (NGC 5128). A giant elliptical galaxy crossed by a dramatic dust lane, and one of the brightest radio sources in the sky. It needs longer total integration than the clusters, but small scopes capture the lane well.

Jewel Box (NGC 4755). A compact open cluster beside Beta Crucis in the Southern Cross, with one obvious red supergiant among blue-white stars. Keep exposures short to hold the star colours.

Sculptor Galaxy (NGC 253). A big, dusty spiral seen almost edge-on, bright enough for a small refractor. It passes almost overhead from New Zealand in spring.

Lenses and small refractors

You do not need a large telescope for any of these. A camera with a 135 mm to 300 mm telephoto lens on a small tracking mount will capture M42, the Eta Carinae region, the Magellanic Clouds and Omega Centauri. A short refractor of 60 to 80 mm aperture with a focal length of around 350 to 500 mm is the classic next step: forgiving to guide, wide enough for the big nebulae, and light enough for a modest mount. Galaxies like Centaurus A and NGC 253 benefit from a little more focal length.

Stacking short exposures

Rather than one long exposure, take many shorter ones, from 30 seconds to a few minutes depending on your mount and sky. Software aligns and averages them, cutting noise and removing satellite trails. Also take calibration frames:

Darks, with the lens capped, at the same settings and temperature
Flats, of an evenly lit surface, to remove vignetting and dust
Bias frames, the shortest possible exposure, for sensor read pattern

An hour of total integration on a bright target from a dark site will beat a single heroic exposure every time. Dark skies help most of all, and a moonless night matters more than almost any equipment upgrade. Our links page lists clubs and resources, and our planets guide covers the brighter, easier targets for a first night out.

When each target is best placed

Approximate months when each is well placed in the evening sky from New Zealand:

Target	Best evening months
Orion Nebula	December to February
Tarantula Nebula	December to March
Eta Carinae Nebula	March to May
Jewel Box	April to June
Omega Centauri	May to June
Centaurus A	May to June
47 Tucanae	October to December
Sculptor Galaxy	October to December

Stellarium will show exactly when each target crosses your meridian on any night. The Royal Astronomical Society of New Zealand can point you to a local society, many of which run imaging groups happy to share advice.