Type of pier

I am about the build a 10'X12'observatoty. I am not sure which way to go with the pier.
Atop the pier will be a CI700 mount with a C11.
The pier, from gound level to the top of the pier will be about 68".

My questions are,
Do I make the pier with cement only, or a cement base and bolt a steel pipe to the base?
What size should I make the pier?

Thanks to all for your time and help.

Robert Edwards

There has been much written about pier design from people much better educated than I but here is my two cents. A concrete block about three feet cubed with rebar. Make sure you leave about four pieces sticking up ten to twelve inches in the center to tye the pier into it. Then pour a twelve inch sonar tube up to height. Remember to place anchor bolts for your wedge in the top. A lot of care needs to be taken in making sure your measurments are right. It's hard to change once it sets up.
Ok the short answer, make it all concrete and as much one piece as possible.
GOOD LUCK

Hi Robert,

If you go with a concrete pad with a flanged steel tube bolted on, your options for using different types of scopes in the future remain open. If you pour a concrete pier up to the full height, you are locked into an SCT, MCT, or refractor setup. When aperture fever regains you in its grip, the bolted pier could later be swapped to a shorter one for a Newtonian rig, or even a tracking dob on an EQ platform could be placed directly on the pad or a short riser.

Just my $.02

Best wishes,
Jason Glass