This is NGC 3699. My picture is one of a very few deep and high resolution images of this planetary nebula. I looked around and all I could find was the ESO image in a press release:

ESO image circa 2015 with a 3.6m telescope!It is my hope this new image advances our view of this planetary nebula. It is actually quite large at 6 arcminutes from one side of the faintest bits to the other. The nebula is quite complex and a challenge to understand when looking at it initially.

It really is a mess! However I would like to propose there is some order to this madness. I believe this is a “polypolar” PNe. In a typical bi-polar PNe there is usually a “collimating” structure (perhaps a torus or cylinder) of denser material that forms the “waist” of a butterfly shaped nebula. Think of examples like NGC 2346 and NGC 6302; even the famous Ring nebula is an example. In the case of the Ring we look perpendicular to the cylinder/torus of the constraining material and the bi-polar outflows bubble out both towards and away from us forming “rings” from the limb-brightening of the bubbles’ boundaries.

NGC 2346 (Adam Block) NGC 2346 - SchulmanT - Adam Block (11-01-12).jpg M57-HST-LBT-Blend Robert Gendler M57-HST-LBT-Blend-SS (1).jpg

However NGC 3699 looks nothing like these. Instead when I saw my first OIII images of this thing, it reminded me of a paper I read on NGC 2440. You can read my old write up about this PNe and learn more about it.

Many planetary nebula exhibit multiple lobes at different rotated orientations. NGC 2440 show this if you look closely at the pattern…

Annotated version of NGC 2440The morphological model and idea of polypolar nebulae come from these papers:

1. J. A. López, J. Meaburn, M. Bryce, and A. J. Holloway2, 1998. The Morphology and Kinematics of the Complex Polypolar Planetary Nebula NGC 2440. THE ASTROPHYSICAL JOURNAL, 493:803-810
2. Paulo J.A. Lago, Roberto D.D. Costa. 2016. NGC 2440 : A morpho-kinematical model. Revista Mexicana de Astronomía y Astrofísica Vol. 52, pp. 329--337

The theory that the astronomers propose to explain all of this is that these kinds of PNe were formed as part of a binary star system and different epochs of mass loss (outflows) results in the rotated bi-lobes we observe. The multiple bipolar lobes at different orientations are produced by episodic outflow events where the ejection axis has changed between episodes. The binary star hypothesis is the leading explanation because a precessing binary system naturally produces a changing outflow axis over time, with each major ejection event producing a new bipolar lobe at a different orientation angle.

I think this is exactly what we are seeing with NGC 3699. However, there are no kinematical studies of this nebula as far as I know. Looks like an excellent project to me! If I squint hard I think I can see 4 or 5 different bi-polar outflows at different orientations.

My polypolar guessesIt might help to look at the starless version. Below is what I was working with before I carried forward and made additional contrast and color saturation adjustments.

Starless with minimal processing. So that really is the story for this that I thought was interesting. In terms of processing this object is overwhelmingly bright in OIII. Thus the significance of the Ha was increased by about 2 times to have it scaled up enough to compete with the OIII. There happens to be some background H-alpha emission in the field as well. I do think the slightly bluish faint star in the center is probably the binary system (and we are seeing the white dwarf). I used narrowband normalization as is typical to achieve the more pale blue (rather than green-blue which looked to whitish in this field). This nebula is very “soft”. There are very few sharp small details to be found. I did apply a tiny amount of LocalHistogramEqualization as well as the High Pass Filter with OverLay blending technique to this image. These two steps give the nebula a little more definition and I think helped me see the structures I describe in the text above.

I publish both a cropped version and the full field.