Cygnus Wall ang Gulf: This crop from a wide-angle image of North America and Pelican Nebula depicts a very interesting area called the Cygnus Wall on the left and the Gulf of Mexico in the center. The Cygnus Wall represents a so called ionization front, where the intensive radiation and star winds of massive young stars convert a cold molecular cloud into ionized hot gas, thus making it visible and creating dramatic wall structures. The Gulf area in the center is a huge dark nebula where the light of the background stars cannot penetrate the cloud.
In addition another impressive ionization front can be seen at the top of the image in the head of the Pelican.

The image was composed from frames taken with three different narrow band filters letting pass only the H-alpha line of hydrogen, the [OIII] line of oxygen and the [SII] line of sulfur. The composition was done using the socalled Hubble palette for arranging the colors.

Have a look at the Hi-Res version for a closer inspection of the intricate marble-like structures of this beautiful skyscape.