Observatory Construction  

Click here for pier drawing

Building the Pier

The pier consists of cement, sonotube, and an 8" x 5' PCV pipe. I designed 2 aluminum plates to attach the wedge to the pier. The bottom plate attaches to the concrete, while the top plate accepts the wedge. The reason for having two plates is to allow the top plate to be leveled, making wedge adjustments cleaner. The bottom plate was installed when the cement was poured. To connect the bottom plate to the concrete, I used 4 3/4" bolts of various lengths (10", 8", and 2 @ 12") attached with nuts to the bottom plate.

Click here for top plate drawing
Click here for bottom plate drawing
The top plate has holes and slots after the design of the Meade heavy duty tripod. I made several prototypes out of wood before finalizing the design. I brought these drawings to an excellent local machine shop called North American Tool and Machine in Charlton, Mass., where the plates were manufactured for a very reasonable fee.

It took 11 80lb bags of concrete to fill the hole, the sonotube and the PVC pipe. The concrete was delivered with ease by my Patriot Blue 2001 Dodge Dakota - 4 full size doors, huge, comfortable interior, heavy duty package, chrome tie downs, yeah baby! Oh... the pier... to keep the arrangement solid and stable, the plates are 1" thick aluminum with 4 hefty 3/4" nuts and bolts making the connection between the plates. I got the nuts, bolts and PCV at McMaster-Carr, I ordered everything on-line and had zero problems, they did a great job. That said, I used 24 of those 3/4" nuts which added up to some cash!

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