Telescope with swappable lenses
You can swap lenses by rotating two wheels while seeing exactly what is going on inside. This helps you understand what is going on in the telescope. By swapping the lenses you can change the zoom from 0.2x to 10x twisting the focus knob will move the objective lenses and focus the telescope.
The telescope can be panned, and tilted. The tilt is achived by a sliding piviot, so it rotates around a point above the centre of mass, so it naturally sits approximately level.