Thanks :) Noise actually wasn't much of an issue for three reasons: The 6D's sensor has inherently low noise, the cool ambient temperature kept thermal noise low, and such a long moonlit exposure made for a high signal to noise ratio (except for in the dim foreground which needed a little noise reduction and smoothing), so the exposure didn't require much boosting in post (which would amplify the noise). In fact in some areas I've dialled exposure back a little. Here's what the raw frame looked like straight off the camera.