North America and Pelican nebulae wide field

North America Pelican wide field Sergi Verdugo

DETAILS
Exposure: 27x300" @ ISO 800
Lens: Nikon Nikkor 180ED 2.8 AiS @ f4
Filter: Hutech IDAS LPS P2 2"
Mount: Skywatcher EQ6 Pro
Camera: Cooled Canon 50D
Date: 25th June 2011
Location: Planes de Son (Lleida, Spain)
Comments: In order to avoid difraction spikes, I used an adapter ring from 72mm to 48mm on the front of the lens to stop it down to f4. I screwed the IDAS LPS 2" filter on that ring.

The North America Nebula (NGC7000) and the nearby Pelican Nebula (IC5070) are parts of the same interstellar cloud of ionized hydrogen (HII region). In the visible light NGC7000 resembles the North American continent, with the most relevant resemblance being the Gulf of Mexico, and IC5070 resembles a pelican in shape, hence the names.
Between this nebular complex and the Earth lies a band of interestellar dust that absorbs the light behind it, and thereby forms the shapes we see. The distance of the nebula complex to the Earth is a mistery, current estimates put it at about 1800 light-years from the Earth, and its absolute size would be 100 light-years.
There is another mistery surrounding the North America nebula, involving the star or group of stars responsible for ionizing the hydrogen so that it emits light. The infrared images from some big telescopes hint that the missing stars are somewhere behing the Gulf of Mexico portion of the nebula. Other sources say that the star inducing the ionization is Deneb.