Combination of 20, 3 minute images using an H-alpha filter and 15, 3 minute images using an OIII filter.
SBIG STL-1001E CCD camera. 300mm f/6 newtonian telescope at prime focus.
RCW 58 has been designated as an emission nebula, however looking at the regular shape and the way it surrounds the bright blue star, I am more inclined to consider is a mass-loss star, similar to NGC 6164/6165. Unless the bright star is not really the source of the nebulosity, I would doubt that it is a planetary nebula.
This curious object is located in the southern regions of the constellation Carina, about 5 degrees south-east of the eta carina nebula.