Extremely Rare - Mandel Wilson 9 - Galactic Cirrus in Apus

Deep in the South constellation Apus lies a truly spectacular field of nebulosity. Not far from the South Celestial Pole (at declination -80º), this nebula is very rarely captured, especially in full colour. This image shows a region catalogued by Steve Mandel and Michael Wilson in early 2000s as the 9th and last entry to their “Catalogue of Unexplored Nebulae” [1]. This pioneering project identified the interstellar clouds in optical light, before only known to professional astronomers through infrared surveys. Mandel named the nebulae Integrated Flux Nebula, or IFN, a name that is frequently quoted in amateur astrophotography, but seldomly used in professional astronomy, where “galactic cirrus” is preferred.

The Galactic Cirri are veils that surround our galaxy – made of dust and gas in the interstellar space. It was first noticed on optical glass plates recorded at Palomar Observatory and subsequently cataloged by B. T. Lynds, in 1965. In the 2000s, Steve Mandel noticed faint cirrus in deep, wide field photographs near the North Celestial Pole, and labelled the nebulosity as the IFN, or the Integrated Flux Nebula. [2] It has incredibly low surface brightness, at ~22-28 mag/arcsec² (fainter than the darkest sky background on Earth), thus it is not easy to capture!

Source: Gabriel Santos