Tele extenders or teleconverters are a great way to increase the zoom on your camera lens. One day I thought to myself, what if you could stack these. Turns out you can. And pretty much as many as you want, or can afford. These guys stacked 5 of them with a 800mm lens and used the monstrous setup to photograph the moon. It turned out pretty well.
Of course using extenders comes at a cost, reduced aperture or captured light. So you will need longer exposure times. Also it makes it harder to get the image perfectly focused. But apparently it can be done. Here are the results.
Shot with a Canon 1D Mark IV, 800mm f5.6, and 5 2x teleconverters! An equivalent of 24,800mm was achieved with this experiment!
And here is a video shot using all 5 extenders.