"PS: Be sure and turn OFF the IS on your lens when using a tripod. If you're going to use a tripod (I certainly would for this kind of image) you might as well use your mirror lock-up option to reduce camera vibration. Along with mirror lock-up it's best to use the shuter release delay timer to provide a 2+ second delay between pressing the shutter button and when the aperture actually opens. That allows vibration in the tripod to settle before the image is captured. That in combo with mirror lock-up are critical for getting the sharpest possible images."

Wow! Back to the operation manual for me!

Thanks for all the input. Perhaps I will get another chance this evening...

Andrew