This image is a collaboration between Stefano Cancelli and I. He imaged and processed a luminance version that has nice detail in the core. I combined it with my version that was processed for colour and details elsewhere. We collected the frames back in 2009 but I just recently made the final tweeks and am now happy to share this on my website. The field of view is approximately 1100mm in focal length taken with an APS-C sized sensor. Here is the blog post giving much more in depth information on how this image came to be. http://www.weatherandsky.com/blog/2013/10/collaborating-in-astrophotography-m31-andromeda-galaxy. Stefano's Website is http://www.astrogarage.com