TheSkySearchers

JayTee wrote: ↑Sat Jul 13, 2019 12:07 am Typically the pier is disassociated from everything else, the obsy floor especially. So, where are these vibrations you are mentioning come from?

Cheers,
JT

KathyNS wrote: ↑Sat Jul 13, 2019 11:31 am I have never heard of anyone trying a base like that. A flat plate of typical 1/2" steel stock would, I think, be very vibration-prone. But, since you specified 6-8" thick, that might be enough to stop any flexing.

It would have the advantage of being moveable (if not exactly portable) in the event you move, more so than leaving a bunch of concrete in the ground.

Why not try it?

My first pier installation was a plywood pier standing on firm-packed ground, anchored by four steel rods driven 4' into the ground. I was surprised at how vibration-free it was. I now use the same pier bolted to a concrete foundation, and it is not as vibration-resistant as the original. Still good enough, though.

mcolbert wrote: ↑Fri Jul 12, 2019 11:09 pm I'm not too sure if this is the best sub-forum to post this in, so if it is better in the DIY section, mods please transfer.

Copy from another forum;


most threads on different fora describe steel piers (or wood etc) atop a concrete base. So I wonder which would reduce vibrations better, the steel pier on a concrete base or a steel pier bolted to a square yard of steel, say about 6-8 inches thick?

I was wondering more if there would be similar benefits in dampening time if a metal base were to be used and the vibrations travelled horizontally rather than vertically.


Thanks

OhNo wrote: ↑Sun Jul 14, 2019 3:57 am I am coming up on the one year anniversary of putting my pier in. I have only used a tripod a handful of times since I installed the pier (and I attempt astronomy about 300 days of he year). One of the real benefits is I've only had to polar align a couple time since it's installation. My pier diameter and depth below ground could have been wider and deeper....

That said, you're asking all the right questions, and received good answers. You have to consider the soil type and your environment. Soil like my pier is in (clay) and is well drained is fairly stable. However I live in an environment that has months of freezing that can drive frost deep into the ground. The the thaw cycle kicks in. This yearly cycle has been known to jack things out of the ground.

IMO stability and resistance to vibration (oscillation) is the goal, especially if your thinking astro-photography. There are lots of great ideas on the net for pier designs, and some that woulda/coulda/shouda been thought through some more. If your no going to be in a location for the long haul, you're wise to consider the portability, I don't regret drilling a hole, using a scrap grain auger tube and pouring some cement. But I had the hole auger, form, and a wheel barrow, little money and a dream. The in ground pier will outlast me.... And as I'm on a farm a pier isn't likely going to devalue my property when the time come to sell.

Hope this helps!