OK, VERY first shots. These were taken from my driveway, all to the east. Still have some focusing issues to resolve (!). All were tripod mounted, timer shots, ISO 200 (Program mode), either 1/40 or 1/50 second exposure, no aperture data, but the scope is about an f/14.
White van: ~450 yards/410 meters
Small peak: ~7,800 yards/4.4 miles/7,100 meters
Large hillside: ~ 11,100 yards/6.3 miles/10,200 meters
(Google Earth is your friend!)
I had a couple closer, but the focus was even worse. The first trend I note is that this would be great for shooting mountains from 20 miles away - focus tends to improve with distance, even though the apparent sharpness through the lens seemed to be the same for all. The image is REALLY dark through the lens, so matching focus was a bit of a SWAG.
I also think that placing the tripod on a softer surface (lawn instead of concrete driveway--vibrations dampened more), and using the wireless remote after giving the rig time to settle down instead of the built-in timer should improve the images. Yeah, I was in a bit of a hurry.