An Inexpensive Piggyback Mount
January 2022 :
One of the simplest ways to piggyback a camera on a telescope tube is via a screw or stud that extends out a threaded hole on one of the telescope tube mounting rings and into the ¼-20 hole found on the bottom of most cameras. With this single point attachment the camera is susceptible to swinging sideways rather than remaining stationary when the telescope is turned, particularly when the camera has a long lens attached to it.
An alternative mounting method is described here. In figure 1 two pieces of tongue and groove board are fastened to a flat board which serves as a base plate. Two countersunk holes in the base plate are positioned over the threaded holes in the two telescope mounting rings. The bevel head screws shown in the photo are inserted in these holes.
Another piece of tongue and groove board is shown in figure 2. Two wooden dowels along with a ¼-20 screw that protrudes thorough the board cradle the camera as shown in figure 3. (The head of the screw is countersunk on the other side of the board.) Note that a piece of plastic tubing has been slipped over one of the dowels to obtain a snugger fit for the camera.
The board that cradles the camera is slid onto the base plate as seen in figure 4. The tongue and groove arrangement provides a pair of guide tracks for the cradle. A bolt is inserted in a clearance hole behind the camera to pin the cradle to the base plate. The red elastic band stretches over one set of tracks to further secure the cradle to the base plate. The blue elastic band fits into the other track to remove any play between the cradle and base plate.
In addition to preventing sideways swing this homemade mount allows the camera to be easily removed from the telescope. I do not know if anyone has thought of this idea before. It is an alternative to more expensive mounting solutions.
