Barnard 31 is a dark nebula in Orion. It’s the dark swath on the left hand side of this image but the red area of hydrogen emission also contains objects from Lynds Dark Nebula catalog and a reflection nebula though, it doesn’t seem to be in the major catalogs. As a result, there isn’t much I can say about the nebulae in the image.

This is 22 hours of HaLRGB data. For all the technical details, see astrobin.