RCW75 (Rodgers, Campbell & Whiteoak) is also known as Gum 48a and is an HII emission region in the constellation of Centaurus about 6200 light years away. The region surrounds a young star cluster known as Stock 16, which is part of the Centaurus OB1 association (ie a gravitationally unbound group of stars). The open cluster Stock 16 can be seen above the "elephant trunk" shaped molecular cloud and the star at the top (TYC8994-2215-1 (HD 115455) (see https://pbase.com/gailmarc/image/172622003) is thought to be driving the ionisation responsible for the emission.

I started imaging this in 2015 and finally finished it off very recently with colour & luminance. This is quite a tricky object to do justice to!