Ahh, the Cygnus Egg! I worked pretty hard on this one. This is a very, very small and dim target in a dense star field and it presented numerous new challenges for me.

For those unfamiliar with this object, in the 1960s it was first cataloged as a galaxy pair. Later, in 1975, more accurate properties were first documented. In more recent times, thanks to some very detailed images produced by the Hubble Space Telescope, it’s true nature is known and is classified as a bipolar protoplanetary nebula (PPN). The protoplanetary phase is a short-lived (on stellar scales) time period between life as a giant and the planetary nebula stage. The PPN is actually a reflection nebula of sorts, where the host’s star light is actually reflecting off the atmosphere it is in the process of shedding. This is in contrast to the later planetary nebula stage which is an emission nebula. The stellar wind from within creates shock waves through the ejected media and ultimately this process is creating the shape of the planetary nebula which will follow.

The Egg Nebula was first named due to its visual appearance and may not be the best moniker, but it has stuck. In the case of this nebula the morphology has taken on an axially symmetric or bipolar shape. The causes are only theorized, but it is a fairly common outcome for PPNs. High energy stellar light is reflected at opposite ends and a perpendicular dusty disk envelops the core. The Egg Nebula seems to have high angular momentum which creates a space for the interior light to shine through at the poles of the disk. In this example, we are viewing the nebula edge on. So the disk blocks the light from the host star, and all we see are the searchlight beams extending away in either direction. HST images show faint shells carrying a number of shockwaves. In my images these knots of material can be seen clearly in the beams, and only faintly in the surrounding matter.

For this image I tried numerous tricks to improve the resolution. But, in the end I was asking too much for my seeing conditions. It is a very challenging target. The nebula measures 30”x15” (YES! 30 arcseconds by 15 arcseconds) and is documented to be 14.0 magnitude, though I think the low surface brightness of the outer area puts this in much more difficult territory.

Rev A - Original

Rev B - Original + Detailed inset at 2x Drizzle

Rev C - Center crop at .57"/px and a little more contrast

Enjoy!