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Cement or Steel for Pier?

Started by desoto, 05/19/2004 03:00AM
Posted 05/19/2004 03:00AM Opening Post
(note: posted this in "Equipment", but not much interest, so am trying this forum--This topic may have been beaten to death like "maple vs. rosewood" over in FDP--if so, please let me know)

I need to mount my mount (Paramount ME + RC12.5" scope) several feet above the ground to clear a deck. I will pour a concrete footing, and I could use sonotube to make part or all of the pier itself out of cement. I will then either attach the mounting plate directly to the concrete or to the pier. Is there any consensus as to whether it would be better to use a taller steel pier and less cement, or a longer cement pier and less steel? Let's say that, for argument, that I need about 5' above ground for the mount. Thanks in advance,
Andy
Posted 05/19/2004 03:48PM #1
Hi Andrew,

I recently had to make a similar decision on what to make my pier from. I have a 10' homedome that rests on a free standing deck. I elected to go the steel route as I wanted to be able to easily remove the pier when I move. I have an AP1200 GTO with several different ota's. Roland Christen told me that a 10" diameter pipe is more than sufficient for the 1200 mount for imaging applications. My actual pier ( still under construction) will be two sections totalling 6 feet and is made from standard 12" pipe. It's about 12.75" OD and ~.25" wall. This will be bolted to a massive footing that is just above grade. Telescope piers can be approximately described as pendulums and resistance to deflection is proportional to the cube of the diameter. Wider is better but not necessarily what you have to have. Many people have very good results with the LeSeur 8" piers. I was fortunate in that my steel was free so I opted for the large diameter. I will not be filling my pier with sand either since imo this adds unnecessary mass to the "pendulum".

Mike