Sh2-278 sits halfway between M42 and the Witch’s Head Nebula, about 2.5° north of Rigel. It has a triangular structure that is prominent in H-alpha, surrounded by several faint reflection nebulae (LBN964 to the east, LBN945 to the northwest, and LBN937/LBN942 to the north). It is an incredibly pretty and unique object, but it is very faint. The combination of dim molecular cloud with ionized hydrogen makes it challenging both to capture and to process.
The glow here may be extended red emission, I can’t say for sure, as there has never been a single paper dedicated to this object. It is only mentioned in catalogs and survey papers, as far as I can find. It sits just off the edge of the Orion A molecular cloud, the cloud containing M42, but it is not clear if it is a remnant of that group or a distinct cloud. It was first noted by H.M. Johnson in 1955.
- Exposures:
- Ha: 30×300s
- R, G, B: 20×180s each
- Total exposure time: 5.5 hours
- Taken remotely from DeepSkyChile, Jan 24 and Feb 1, 2024
- Telescope: Takahashi TOA-130 with flattener (f/7.7)
- Camera: ZWO ASI6200MM-Pro
- Mount: 10Micron GM1000HPS
- Acquisition: NINA
- Processing: AstroPixelProcessor, PixInsight
Deep-sky Imaging 