RCW58 is a stunning Wolf-Rayet shell in Carina that should be on every list of top deep-sky objects. It's location deep in the southern skies means it is not seen as often as it should be. Nearly every image I’ve seen of it is a close-up (every other image I could find on astrobin is), revealing the iris-like striations around a central star (WR40 = HD 96548) that make it look like a flaming eye. Here, I’ve framed it wider, revealing the dense Milky Way stars it sits in front of, as well as one of the many dark nebulae in this area. As best as I can tell, the dark nebula at bottom-left is catalogued as two objects: the left part is Dobashi 5806 and the right/central part is Sandqvist 128. The bright star is magnitude 5.2 HD 97583. RCW58 is 9100 light year away. The Wolf-Rayet stars were known since the late 19th century, but it's not clear to me in the literature if anyone observed or photographed the nebulosity around WR40 before Rodgers, Campbell, and Whiteoak in 1959. The nebula is fairly bright, so it seems possible there were unrecorded observations.
In processing this, I created an RGB image, an H-alpha image, and an OIII image. I stretched them all to the same background level, then I set the red channel to be the max of the RGB image and the H-alpha image. Likewise for blue and OIII. This brought the much brighter narrowband data into the image without affecting the color balance of the rest of it.
I also found a tiny planetary nebula in the HOO data: PN G291.9-04.0. It’s at the 11 o’clock position, about a third of the way down from the top:
And if you really want a more "typical" view of RCW58, here is the HOO view of the nebula only, processed from the same data:
Comments