Many years ago (early 80s or late 70s), I bought a cardboard "device" which I think was called "Planet Timer" and I think was sold by Edmund Scientific. Does anyone have any information on this device? Google was unhelpful.
The device had concentric revolving circles around a fixed Sun at the center. By revolving the circles to the current time (via tables provided with the device), you could presumably see what constellation each planet was in. You could also use it to approximate planetary conjunctions.
The circles were equal distance from each other, so I'm pretty sure the device couldn't actually have worked, but I'm curious to see if I can find out more about it.
Note: this is not a "planisphere" device, which did work, and for which I can still find plenty of information.