I'm in the process of installing a pier in my garden. I'm putting a concrete plinth onto sandstone.
My question is would it be worth putting a layer of vibration isolation material underneath the pier, so that it sits between the bottom of the pier and the block of concrete. I was thinking this would help absorb extraneous vibrations, passing vehicles being the most obvious.
I'd concur. If it's really necessary later, we used to mount vibration sensitive hardness testing equipment in industry (steel mill) next to a processing line that vibrated the whole floor noticeably, by simply sitting the machine onto a bit of plywood which floated on a 'sheet' of 8 x 6 = 48 tennis balls trapped in an appropriately sized plywood frame.
Worked perfectly and removed 99+% of serious vibration as a simple damper.
This would be a simple addition to the slab later if vibration is an issue.
The issue with the under-concrete mounting is that if there's any dirt, the swelling of wet soil might cause an issue with slab cracking or out-of-level.
(I bought that Meade LX90 off you a while ago, but new streetlight plus neighbours floodlights plus a 40kg pup have completely stopped any observations.)
If your footing is adequate for your pier and your pier diameter is adequate then it’s probably not required unless your imaging at ridiculous focal lengths , +3000mm
My rig in Sydney ( EQ6-R + 6” Newt , soon to be 8” Newt ) is sitting on pavers ( compressed river sand ) near my pool and I’ve done jump tests near the rig whilst guiding and no issues at all with Star shape ( focal length 900mm , soon to be 1050mm )
My NexDome Obs down South has an EQ8-R mount using the monster pier tripod with a 10” f5 Newt ( focal length 1280mm ) , sitting on 3 concrete piers , 300mm dia and 1200mm high ( 750mm in the ground and 450mm above ground. Piers are into a 500 x 500 x 300mm footing ( with 12mm steel reo rods and mesh ) Location site on clay.
Again I performed a knock test with a rubber mallet on the pier base footing whilst imaging , no issue with PHD2 guiding.
I’m sure that really high piers ( 1.5 to 2m + ) or narrow piers 100 to 200mm dia would be more susceptible to vibrations
