May 12 2011
To go with my observatory design I have also decided to design my own pier and pier plate adapter.
Lots of hours have been spent trawling the internet and forums to find designs, ideas and theories on how to make a good pier and adapter. The plan will be to make a steel pier which can be moved should we move house.
There is a very interesting article on the Cloudy Nights Forum discusing the various theories around pier diameter to control movement.
It puts across some good theory, in a language I can understand! However, when using the figures listed I ended up with a massive pier, far larger than the ones that I have seen around here and for sale commercially.
So after some more research I finally decided to reduce the figures slightly and came up with this initial design, as attached.
It is based on a direct connection pier where the pier adapter for the mount is bolted directly to the pier.
Upon my research I noted three key points to a good pier design:
1. The ability to level the top of the pier;
2. The ability to fine tune the pier adapter to point North;
3. The ability to attach the mount to the pier / adapter using the threaded bolts from below.
Levelling the pier still needs some resolution but ultimately will also boil down to ensuring the top of the pier base is level and that the threaded rods for connection are vertical and plumb. With this is mind Im sure I can fine tune the levelling of the pier with some sort of shim or gasket.
In the designs I have noted the pier usually has a secondary pier plate to which pier adapter affixes to. The connection between these two items often contain slotted holes so that the pier adapter can be fine tuned to face North (Also, being connected with protruding threaded rods, also gives the ability to get the plate level.). In removing this set up on my design I needed to figure a way to achieve such fine tuning.
Now with my mount (NEQ6 Pro) as well as most EQ mounts there is a small amount of adjustment with the azimuth adjustment bolt. I have decided to add further adjustment by transferring the slotted holes to the base of the pier where it is connected to the pier base.
In order to allow access to the underside of the top plate a slot is cut out of the pillar. This allows access to the 6no holes for attaching the pier adapter and central hole for attaching the mount. The 6no pier adapter holes are either spaced for a generic pier adapter or custom spaced for a custom made pier adapter.