NGC 7023 - The Iris Nebula

I used the dark skies at GSSP 2015 to image the Iris Nebula - a reflection nebula that is 6 light years in diameter and at a distant of 1,300 light years distance. The nebula was discovered  on 18 October 1794 by William Herschel:
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(click image for full-size)

This image consists of 5+ hours data (100 min luminance and 75 min red, green blue each).

The blue color comes from the young, hot star in the middle (SAO 19158) - it has 10 times the mass of our sun. Zooming into the center of the nebula shows some reddish glow:

This is the result of ultraviolet light (from the center star) converted to visible light.

I found this great sketch on the web that illustrates how we see this nebula:

Title: Structure and physical properties of the bipolar outflow source NGC 7023

Authors: Watt, G. D., Burton W. B., Choe, S.-U., & Liszt, H. S.

Journal: Astronomy and Astrophysics (ISSN 0004-6361), vol. 163, no. 1-2, July 1986, p. 194-203

Bibliographic Code: 1986A&A... 163.. 194W