I love imaging and examining unusual deep sky objects. This object, the Egg Nebula, is one of the most unusual. I have read a number of articles and papers about this object and still have more questions than answers.

This object is a tiny nebula located 3000 light years away in the constellation of Cygnus at a declination of +37 degrees. The nebula spans 45 arc-seconds in our apparent view, about the same size as Jupiter. Its true diameter is a little over one-half of a light year. The nebula is formally known as PK 80-6.1. I could not find the source of the Egg Nebula nickname - I have a hard time envisioning this object shape as an egg.

This nebula was the first of its kind to be identified. Scientists believe that it is a ‘preplanetary nebula’, a brief stage in the late life of a star between being a red giant and becoming a planetary nebula. The star is at the center of the image, surrounded by a thick torus dust cloud (vertical to our view). This cloud is comprised of the outer layers of the star which has been shed for the last few hundred years or so.

The four lighthouse-like beams which stream out from the star, two left and two right, are fascinating to me. Each opposite pair of beams are almost, but not quite, lined up linearly. Nobody really understands the nature of these jets, which must be sharply focused at high velocity to create such long, distinct light paths through the dust cloud. Many PN are multi-polar and this one appears to also have that potential, given the 4 jets which currently are present.

The beams are not a constant brightness along their lengths, reflecting variations in the density of the dust cloud that surrounds the star and which dim the beam in the denser parts. Scientists believe that these variations are due to concentric rings in the cloud which now surrounds the star, caused by periodic recent burps of star-ejected material.

So why is the left hemisphere blue and the right hemisphere orange? It could simply be that it is some sort of an artifact from my telescope. But is it also possible that we are viewing the nebula at an angle in our apparent view and that we are actually seeing the light from the fast moving jets being optically red shifted (moving away from us) and blue shifted (moving towards us)? Light would have to be travelling awfully fast for this to be the case, but I have read that some types of bi-polar jets travel close to the speed of light. This coloration is the aspect of this object that intrigues me the most, and which was not addressed in any of the material that I have read on this object.