2000mm Nikon Mirror Lens
Check out the size of this fixed Nikon 2000mm mirror lens at f/11 which I was told weighs in about 60lbs and was valued between £6000-£7000 second hand a few years ago.
This guy who is part of the 24hr surveillance team on the nesting peregrine falcons on the nearby cliffs very kindly offered to set it up on my own Nikon camera to try out. I didn't take him up on the offer but perhaps I will on another occasion.
The peregrine hide is approximately 25-30 mins walk from the Visitor Centre at New Lanark along the Falls of Clyde walkway, Scotland.