Thanks Bert.
I will keep that in mind. I will be building next to a fairly large swimming pool. I believe the builders hit rock there so perhaps I can attempt to get down to the rock.
Greg.
Quote:
Originally Posted by bert
Hi Greg,
Its the depth of the pier in the ground that matters more than its mass. I used a steel reinforced concrete footing around 400mm diameter and 1200 deep for my observatory. Its rock solid and the mount is mounted 1800mm above ground level. Some people just put a cubic meter in a shallow pier and it can work, but its far more cost effective with the deep pier and more stable.
The slab is not likely to cause thermals, and pavers have the similar thermal mass. Slabs make things a lot neater inside as well. I built an observatory for a friend on this forum and has two piers mounted, he only isolated the pier that is doing the long focal length (3m), and not the wide field setup (500mm). I dont believe he is having vibration issues with the unisolated pier. He used expansion joint foam to isolate the pier from the main slab.
Brett
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