Home to some of the nearest molecular clouds, the constellation of Chamaeleon is filled with many dark nebula complexes. The Chamaeleon I complex is one of three large clouds found in this southern constellation and has an age of 2 million years. The distances of the three main clouds range from 520-580 light years and are also isolated from other major star forming complexes. The Chamaeleon I complex is a site of low mass star formation, which is characterised visually by various reflection nebulae including IC 2631 to the north and the blue nebula Ced 111 and the white reflection nebula Ced 110 to the south. The great obscuring mass of thick brown dust in the region absorbs the blue light of distant stars making them appear much redder than they actually are. This process of interstellar reddening also affects the light of distant galaxies in the line of sight, making them look less blue. Despite the copious amounts of dust, the Chamaeleon I complex is regarded by astronomers to impose only a moderate level of extinction on the background starfield in comparison with other dark nebulae. The Chamaeleon I complex is near the south celestial pole and is situated at the edge of the Scorpius-Centaurus OB association. The cloud is illuminated by massive stars that belong to a subgroup of this OB association. Due to its proximity, the Chamaeleon I complex has been subjected to many searches for young stellar objects by many astronomers including Karl Henize in 1963. Recent surveys in the past two decades have also yielded a large sample of YSO's, including the first X-ray emitting brown dwarf, which was discovered in 1998. Young stellar objects have also been discovered in various infrared surveys of the clouds. The cluster of sources associated with the complex is split into two northern and southern subclusters and the cloud contains 200 known low mass YSO's. Analysis of data predicts that star formation began 3-4 million years ago in the northern half of the cloud and 5-6 million years ago in the southern half. Star formation in the cloud is still ensuing at a declining rate until eventually it will completely cease. Other optically visible signs of star formation in the cloud are represented by small Herbig Haro objects and outflows. The first Herbig Haro objects to be discovered in this complex were found in a survey for Herbig Haro objects in dark clouds by Richard Schwartz in 1977. They include HH 48-9 and HH 50. Due to its tiny size, HH 48 isn't visible in this widefield image but the bright Herbig Haro objects HH 49 and HH 50 are prominently visible in the region between Ced 110 and Ced 111. HH 49/50 are associated with the largest outflow in this complex, a giant outflow with a length of 27 arcminutes (or 6.5 light years) and its source is the protostar Cha-MMS1. Spitzer infrared images of HH 49/50 reveal infrared emission associated with them. This infrared nebula has an incredible shape of a "tornado" formed by a pair of twisting helical filaments. Deep imaging surveys in the past decade have found a total of 30 Herbig Haro objects associated with 20 separate outflows. Also visible in the image is a unique curiosity, a colourful orange nebula below the reflection nebula Ced 111. This is the Chamaeleon Infrared Nebula, a bipolar infrared reflection nebula that also happens to be visible optically. Its bipolar nature is only visible in infrared images as well as its illuminating source. Studies of the nebula have shown it to exhibit a complex geometry consisting of a disk surrounding the central source as well as bipolar lobes tracing two cavities cleared out by ouflow activity. Infrared images reveal the two bipolar lobes to be separated by a dark structure, which is a circumstellar disk around the central source (description provided by Sakib Rasool) Apo TEC140 (140/f7.2) - FLI Proline 16803 - L (580m) R (90m) G (90m) B (90m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This gorgeous telescopic portrait reveals remarkable details of the region's glowing filaments of interstellar gas and obscuring cosmic dust clouds. Wider than the Full Moon in angular size, the field of view stretches nearly 100 light-years across the nebula. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Eta Carinae is the brightest star at the left, near the dusty Keyhole Nebula. While Eta Carinae itself maybe on the verge of a supernova explosion, X-ray images indicate that the Great Carina Nebula has been a veritable supernova factory (text adapted from APOD). Apo TEC140 (140/f7.2) - FLI Proline 16803 (4 panels mosaic) - Ha (850m) OIII (1110m) R (290m) G (290m) B (350m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
Blazing brightly in the southern sky, the supergiant binary Alpha Centauri is the host of an expansive starscape sprinkled with numerous deep sky objects in this telescopic view. The most visually striking of its retinue of glittering jewels is the exotic and unique planetary nebula Hen 2-111, which is one of 468 planetary nebulae that were catalogued by Karl Henize in 1967. The main central part of Hen 2-111 is a bright peanut shaped core that measures only 29 x 15 arcseconds. However, its most visually striking aspect is a faint giant ionized halo that spans 10 x 5 arcminutes! This extreme structure was discovered by B. Louise Webster in 1978 in deep photographic plates taken with the (at the time) Anglo-Australian Observatory. At an estimated distance of 7800 light years, the entire nebula spans approximately 23 light years! The halo is actually a rare bipolar outflow and the other notable planetary nebula known to exhibit this unique feature is the northern hemisphere nebula KjPn 8 in Cassiopeia. Hen 2-111 exhibits some of the highest radial velocities detected in a planetary nebula to date! The radial velocities of the outer lobes are 370 kms, which is indicative of the high speed of the material ejected. Bipolar outflows with even greater velocities have been observed in a few other planetary nebulae. Almost perfectly symmetrical, the geometric regularity of the outflow is due to the ionized gas flowing outwards along the walls of two bi-conical structures. The twisted appearance is caused by the axis of the structures being viewed at an angle of 45 degrees from our line of sight. The most likely explanation for the origin of the outer lobes is an eruptive event of the central star within a circumstellar disk. To the right of Hen 2-111 is the attractive pairing of the open clusters NGC 5617 and Pismis 19. NGC 5617 is the larger and younger of the two and despite its apparent youthful appearance, it is actually an intermediate age cluster with an estimated age of 80 million years. Contrastingly, the smaller rich condensed cluster Pismis 19 appears much older than NGC 5617 and indeed its golden ancient light betrays its great age of 800 million years! It is at a similar distance to Hen 2-111 of about 7800 light years whereas NGC 5617 is much nearer at 5000 light years. However, it is subject to severe reddening due to interstellar dust between us and the cluster and would shine more brightly if this dust was less prevalent. Pismis 19 is one of 24 open clusters that were discovered by Paris Pismis in 1959 by analysing photographic plates taken at the Tonantzintla Observatory. Also barely visible in the glare of Alpha Centauri is a round broken roughly circular shell, which can be seen to the north of the halfway point between Alpha Centauri and Hen 2-111. This is the supernova remnant G315.4-0.3, which was discovered by Anne Green in 1974 and identified as a supernova remnant in 1975. However, its extremely dim optical shell was discovered recently in 2011 in a search for new supernova remnants in SuperCOSMOS Ha Survey (SHS) images by Milorad Stupar and Quentin Parker. Thanks to Sakib Rasool for suggesting me this little known object and for preparing the above object description. Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (720m) OIII (660m) R (160m) G (120m) B (180m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
