This image uses my new set of Antlia 50mm Pro 3nm Unmounted filters. All except the Ha which is a Chroma Ha 5nm 50mm Unmounted. All filters are 3mm thick, so close to par-focal. I would have used an Antlia Ha 5nm if they made one, but they don't. I wanted a 5nm Ha to pick up the Nii emission which is very close to the Ha.
The Ha emission region SH2-129, commonly called the Flying Bat Nebula, contains the Squid Nebula, designated Ou4, a mysterious, squid-like apparition. This nebula is very faint Oiii emission, but also very large in planet Earth's sky. It spans some 2 full moons toward the constellation Cepheus. This image presents the Squid in its true teal colors, a mixture of green and blue.
Ou4 was recently discovered in 2011 by French astro-imager Nicolas Outters, the remarkable nebula's bipolar shape and emission are consistent with it being a planetary nebula, the gaseous shroud of a dying sun-like star, but its actual distance and origin are unknown. A new investigation suggests Ou4 really lies within the Ha emission region SH2-129 some 2,300 light-years away.
Consistent with that scenario, the cosmic squid would represent a spectacular outflow of material driven by a triple system of hot, massive stars, cataloged as HR8119, seen near the center of the nebula. If so, this truly giant squid nebula would physically be nearly 50 light-years across.
My Collections:
Abell Planetary Nebulae (Complete)Planetary NebulaeGalaxiesSharpless 2 Objects
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