vdBH80 is a small reflection nebula in the centre of the bright rimmed globule SFO 85, which is embedded in the giant emission nebula RCW 113 in the constellation of Scorpius. Both nebulae are influenced by the intense radiation of the energetic and luminous open cluster NGC 6231, which can partly be seen in the top right corner. NGC 6231 is a young cluster with an estimated age of 3-5 million years and contains more than 100 massive stars, including 15 O-type stars. It forms the heart of the Scorpius OB1 association, which is responsible for influencing the gas and dust in the surrounding area. RCW 113 is a large curved HII region that was first noticed in photographic plates in 1955 by Colin Gum and is also catalogued as Gum 55. It was also independently found in the same year by the astronomers Bart Bok, Michiel Bester and Campbell Wade. Its source of ionisation are multiple supergiant stars in NGC 6231. vdBH80 is one of 136 southern reflection nebulae that were catalogued by Sidney van den Bergh and William Herbst in 1975. However, this nebula was noticed earlier in 1962 by the legendary astronomer Karl Henize. At the heart of this nebula is the Be type supergiant star V921 Scorpii, which is directly associated with the nebulosity. This association is confirmed by both the star and the reflection nebula sharing almost identical spectra. Be type stars are intermediate mass stars that are characterised by an association with circumstellar gas and dust. This phenomenon has been observed at all evolutionary stellar stages including pre and post main sequence. A new study of the star whose results were only published this year detected a companion to V921 Scorpii. This has helped confirm a hypothesis that the Be phenomenon is related to interactions in a binary system. The orbital period has been calculated to be 35 years based on earlier observations in 2008 and 2009. High resolution observations of the nebula have detected regularly interspersed substructures, which would imply episodic mass outflow with a period of 25 years, which also corresponds roughly with the orbital period of the companion. The mass loss episodes might have been triggered by the orbital passage of the companion in the system. Another finding of the observations is that the circumstellar disk around V921 Scorpii is aligned with the surrounding nebula along its polar axis. Between vdBH80 and the bottom left corner is a small round faint nebula. This is the planetary nebula HaTr 5 and is one of 14 planetary nebulae discovered on POSS plates in 1983 by H. Hartl and S.B. Tritton and interestingly this catalogue wasn't published until 1985. It is characterised by an elliptical ring with a well defined outer edge. To the north of vdBH80 is the inky black dark nebula SL 19, which blocks the light of stars and dust behind it. It is one of 42 southern dark nebulae that were catalogued by the Swedish astronomers A. Sandqvist and K.P. Lindroos in 1976. 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 (315m) R (80m) G (70m) B (80m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
RCW 75, also known as Gum 48A, is a very active HII region fueled by the young star cluster Stock 16 and the OB association of Cent OB1. Numbers of faint stars found just within the eastern boundaries of RCW 75 are suggested to be low-mass pre-main-sequence stars formed from the interaction of the ionization/shock front from RCW 75 with the adjacent gas and dust complex. Stock 16 and RCW 75 otherwise constitute what appears to be a rather passive star-formation complex. Colin Gum, working at Australia's Mount Stromlo observatory in 1951, completed the first major survey of HII regions visible in the southern hemisphere. He published his nebula catalog in 1955. Although Gum's catalog was largely superceded by the RCW catalog published in 1960 by Alex Rodgers, Colin Campbell and John Whiteoak under the direction of Bart Bok, many HII regions are still referenced by their Gum numbers even today (text adapted from Star Shadows Remote Observatory). Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (240m) R (70m) G (70m) B (120m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
PFP 1 is a large highly evolved planetary nebula that was discovered in 2004 by Quentin Parker, David Frew and Mark Pierce. It is one of the most well known objects discovered in the SuperCOSMOS H-alpha Survey (SHS) as part of the Macquarie/AAO/Strasbourg Ha Planetary Nebula Catalog (MASH) project. The SHS Ha Survey has been crucial in the discovery of extremely faint planetary nebulae and other types of objects that can only be detected with narrowband imagery due to their intense faintness. The MASH catalogue contains about 1200 planetary nebulae and along with other galactic Ha surveys, it has helped to double the number of known planetary nebulae to approximately 3000. PFP 1 is one of the largest planetary nebulae found with an apparent size of 19 arcminutes. It is characterised by a thin faint almost perfectly annular ring with a brighter limb to the north. This bright rim structure is faintly visible in POSS I and POSS II red plates and it is the result of the planetary nebula starting to interact with the ISM. This part is brighter than the rest of the nebula due to the material in the planetary nebula-ISM boundary being compressed, which leads to a brightness enhancement in the direction of motion of the planetary nebula. Few examples of planetary nebulae with ISM interaction are known due to their extremely low intrinsic brightness. Currently 100 are known and the southern SuperCOSMOS H-alpha Survey along with the INT/WFC Photometric Ha Survey of the Northern Galactic Plane (IPHAS) have been invaluable in the detection of more of these rare examples. This stage in the evolution of a planetary nebula precedes the total dilution and fading of a planetary nebula. However, the phenomenon of ISM interaction has been observed in young planetary nebulae with high speed central stars and studies conclude that different stages of interaction are exhibited throughout the life of planetary nebulae. The idea of a planetary nebula interacting with the ISM as it moves through space was proposed in 1969 by the Armenian astronomer Grigor Gurzadyan. PFP 1 lies in an area of relatively low extinction at a distance of 1800 light years and its size is approximately 10 light years. However, the cause of its interaction with the ISM isn't conclusive. It is either due to the motion of the planetary nebula or an encounter with an area of enhanced density in the local ISM as it expands outwards. In addition to its prominent Ha emission, it also contains weak OIII emission as it is a low excitation object. 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 (645m) R (100m) G (60m) B (70m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
