Azimuth Encoder

The Azimuth encoder is offset from the hollow azimuth axle to allow the wires to the azimuth motor to pass thru.

The encoder is driven by a gear connection to the azimuth axle.  The encoder is an 8192 count US Digital encoder, with a 120 tooth gear attached.  The azimuth axle has a 126 tooth gear on it.  The rocker box has a tapered roller bearing inset into the bottom.  The axle is a pipe flange and pipe nipple turned on a lathe to a 1" OD.  The gear and rockerbox tapered roller bearing slip over the axle,  and the azimuth axle gear is "clamped" between the inner race of the tapered roller bearing and the "coupling" nut screwed onto the threaded end of the pipe nipple (azimuth axle).  This not only preloads the azimuth drive roller to help prevent slippage, but allows the preload to be removed and the lifting pads under the rockerbox to lift the rockerbox off the bearings and drive roller to protect them while the scope is being transported.

The encoder is on a spring loaded plate to keep the gears in mesh, and also allow the gears to be swung out of mesh if required.

The entire assembly is enclosed in a small box in the bottom of the rockerbox, with a hinged Plexiglas lid with a hole in the center to allow the azimuth motor wires to pass thru.