The Swan Nebula, or the Omega Nebula, depending on its orientation.
Imaged it using LRGB, first time in doing so. However, I was running out of time, as clouds were moving in. The evening I imaged this, I first took a set at Oiii, which was not my intent, so I had to start again using Hα. The image consists of 1 hour of Hα luminance, and only 10 mins each RGB color.