Hidden in the vast Milky Way starfields of Musca, the faint spidery tendrils of the Ha shell G296.2-2.8 envelop the brighter reflection nebula IC 2966. It is very large with a size of 1 degree, which is equivalent to the area covered by 2 full moons! It is one of hundreds of new objects discovered in the SuperCOSMOS H-alpha Survey. This particular ghostly phantom was found on Ha plates in 2001 by Andrew Walker, William Zealey and Quentin Parker. At the moment its true nature is unknown and some of the possible scenarios concerning its formation are that it might have been produced by a supernova remnant interacting with a dark cloud or more unlikely is that it might be ionised by the central star of IC 2966. If G296.2-2.8 and IC 2966 are related, then based on the distance of 10,700 light years for IC 2966, the size of G296.2-2.8 is roughly 200 light years! Despite its faintness, G296.2-2.8 would look more brighter and detailed in a high resolution mosaic with a larger telescope and is certainly a unique "hidden treasure" of the southern sky.
Thanks to Sakib Rasool for suggesting me this obscure yet intriguing object and for preparing the above object description.
Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (1115m) R (80m) G (60m) B (80m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia