The Pier
Here, you can see the hole and rebar "cage" I used for the pier. The hole for the base is four feet square and four feet deep. The rebar was welded together, and it was designed so that it not only fills most of the hole, but so that it would extend up into the sonotube that would be used for the pier itself.
The ground was all clay, so it was a major chore to hand dig... especially the lower foot or so, because it kept filling up with water after heavy rains!!
What made the digging a little more "iffy" was the fact that I dug this only about eight months after having had open heart surgery! But that's the price you pay if you are an "astro-nut".
The sonotube for the pier has been lowered down around the vertical portions of the rebar cage. It extends down into the hole only about one foot, and is being suspended and held in place with a frame. A few nails go through the frame and into the sonotube, which is enough to hold it suspended to the proper height for when the concrete is poured.
I had decided, early on, that I was going to have a larger-than-necessary pier, so I settled for an 18 inch diameter pier. This certainly was more than enough for my LX-200 and anything else I might shift to in the coming years.
It is very likely that I didn't need all of this bracing to hold the sonotube, but since the concrete was going to be poured down the sonotube and into the base, and since it would slowly fill up, I didn't want to take the chance that the tube might begin to tip at a critical moment. NO WAY was I going to be trying to stop a 500+ pound tube of concrete from tipping if it decided to do so!!
At last, the concrete has been poured and the frame removed. During the short period of time between the pouring of the concrete and when it had set up enough to remove the braces, I inserted into the concrete, four threaded rods for holding the 1/2 inch metal plate that would sit on top of the pier and support my wedge. The four rods were bent into an "L" shape before inserting them into the concrete, with the bottom of the "L" being the portion that was inserted into the concrete.
The plate is 18 inches in diameter and mounts on the four 1/2 inch threaded rods. A temporary form, shown here, is a plywood disk of the same size as the plate. It is held, bottom and top, by nuts and flat washers on the four threaded rods. I made the form approximately level, but I left the final levelling until I had mounted the metal plate, later.