pier size

Hello,

I've poured a pier base ... about a meter of concrete, and set bolts in the concrete so that I can bolt a pier to it. The telescope will be on the second floor of the observatory ... about 9' off the ground. I found a 10' 6" pipe probably 3/8th"- 1/2" thick, with 10" square 1/2" plates welded to either end of the 10' pipe. Will this pipe be sufficeint? what experience have you had with pipe piers?

thanks dan

I personally used a 3/4" wall steel pipe had a bottom plate welded to it. Then filled the pipe up with play sand.
I think that the pipe was 9' long if my memory is right. Took about 450lbs of sand in it