[pmrid (Peter)]

This is a bit of a diversion from the parallel thread on backyard observatory planning. It diverges over the issue of the pier and foundations.

I am buying a small place on Bribie Island north of Brisbane. I'm planning on having a cement slab a little below grass level so I can mow over and around it and also so I can plonk my tripod down as and when I need.

I appreciate all the advantages of a fixed pier with set alignment but for the moment at least, this is not an option. I will probably sink some threaded rod into the concrete so I can - if the opportunity arises later on - put a pier on it. But for now, I plan doing a good string-line to get true south, then using the tripod at full extension, mark the position of the feet on each leg so I can at least have that much head start on alignment when I need it. I will probably set some good-sized bolts into the concrete pad so I can just slot the legs into it quickly and repeatably.

I built a couple of these pads on my farm (with the very generous help of Brundah - Dave) several years ago and visitors found the head start these markings gave shortened the alignment process considerably.

So, my question is how important people think it will be to have some massive foundation either for the slab itself or for a possible future pier. I will be imaging remotely or at least some little distance away from the slab so it will have minor (to the point of zero) vibrations. Also the FL of the scopes I am likely to use don't go above 1600mm.

Love to hear your views guys.

Peter]