This narrowband image with RGB stars shows an emission complex stretching from Simeis 57 (the Propeller Nebula) in the upper right corner down to the bright blue reflection nebulae NGC 6914 (including vdB 131 and 132) in the lower left corner.   The complex is located in the constellation of Cygnus at a declination of +43 degrees.

The Propeller Nebula in the upper right quadrant is a fairly bright emission nebula but does not appear in either the LBN or Sharpless catalogues, nor is it identified in the Astrobin mouseover. Although some refer to this object as DWB 111, the object actually consists of three DWB objects - 111, 118 and 119. Its proper designation is Simeis 57, identified in a paper by Gaze and Shajn in a Crimean journal in the 1950's. The name Simeis originates with an older astronomy facility operated by the Crimean Astrophysical Observatory in the city of Simeiz. The only other popular Simeis object is Simeis 147 (The Spaghetti Nebula).

Because of its unique shape, the Propeller Nebula in the past has been believed to be an outflow from a rotating source.  But recent studies (such as The Peculiar Nebula Simeis 57) indicate that it "appears that the nebula Simeis 57 consists of separate filaments and diffuse emission that together only fortuitously produce the remarkably coherent appearance of an outflow object."  Such a happy accident is one of many that we see in this hobby.

What is exciting the propeller nebula?  The above study indicates it is the magnitude 6.8 star HD 193793, a binary star which includes both a supergiant and a WC7 Wolf-Rayet star (WR 140).  This bright star is seen in the image some distance left of the propeller, using the mouseover coordinates 202028 RA & 435130 DEC.  Notice that this star is at the center of a large cyan OIII arc which includes the propeller.  The paper points out the similarities between Simeis 57 and the California Nebula, in terms of the evolved nature of the exciting star, its location outside of the nebula, the OIII asymmetry and the filamentary appearance.

Extending down the image, through the center column, is a fascinating series of faint emission arcs, not as bright as the Propeller but each complex and interesting.   The arcs face various directions, suggestion a complex driving mechanism with no single dominant force.

In the lower left of the image is another complex object which is shown on the mouseover and features three bright blue reflection nebulae as the featured objects.   NGC 6914 is the most prominent of the reflection nebulae.  Just below NGC 6914 is van den Bergh 132 (vdB 132). Finally, at the lower edge of the image, is vdB 131.