This is a project that has been a long time in the making. I have a small backyard observatory that I use primarily for astro photography. It is a skyshed pod . It is very similar to the HDPE plastic garden sheds you might get at Costco or Sam's club or some other warehouse club. It is about 7.5 feet in diameter.

When I first built the pod in 2009 I did not do a concrete pier for the telescope. Just didn't have the time or money at that point. So I used a tripod for a number of years. This is not ideal for a number of reasons. The tripod takes up a lot of floor space due to the legs and also if your trip over the legs your hard won careful alignment is likely to be effected. 

So I have been wanting a pier for some time. I had some contstruction workers over the house doing some other concrete work. I decided to ask them about the pier on a lark. They quoted me a reasonable price so I had them go ahead and do the work.

Then I needed an adapter plate to mount my Orion Atlas German equatorial telescope mount to the pier. I thought this would be a good CNC project. Here is what I came up with.