RCW 75 (Gum 48A)

Emission Nebula/HII Region, Centaurus

March 2024. Observatorio El Sauce, Chile

RCW 75 (also known as Gum 48A) is an emission nebula region in the constellation of Centaurus. RCW 75 is located at a distance of betwen 5,200 and 7,800 light-years, and is associated with some extensive dark nebulae. At the right edge of the image is RCW 74. This is a major complex with many clusters, HII regions, a WR star and a giant molecular cloud. It appears to be part of a larger structure called the Centaurus Spur.
The RCW Catalogue (from Rodgers, Campbell & Whiteoak) is an astronomical catalogue of Hα-emission regions in the southern Milky Way, described in (Rodgers et al. 1960). It contains 182 objects, including many of the earlier Gum catalogue (84 items) objects. The later Caldwell catalogue included some objects from the RCW catalogue. There is also some overlap with the Sharpless catalogue-2 (312 items), although that primarily covered the northern hemisphere, whereas RCW and Gum primarily covered the southern hemisphere. The RCW catalogue was compiled by Alexander William Rodgers, Colin T. Campbell and John Bartlett Whiteoak. They catalogued southern nebulae while working under Bart Bok at the Mount Stromlo Observatory in Australia in the 1960s.

Telescope: Astro Physics 155EDF (TCC) f5.4
Mount: Astro Physics 1600GTO
Camera: FLI PL29050 / CFW2-7
Guider: Agena Starguide II / ZWO ASI178MM
Filters: Astrodon II 50mm LRGB

L: 68×10 mins = 680 mins, R: 24×10 mins = 240 mins, G: 24×10 mins = 240 mins, B: 24×10 mins = 240 mins

Total Imaging Time: 23h 20m

Data Imaged remotely on 5 nights during March 2024.
Imaged from Observatorio El Sauce, Chile, in partnership with Fred Espenak.
Data acquisition & Processing by David Churchill.