Houghy,
I have a steel pier, 1m into the ground, 1m above. Originally sat in a 1x1x1m cube of concrete but now at it's new home only 70cm deep because I hit rock.
The pier is in 2 halves, bolted together with 8 x 3/4 inch bolts. I did this because I knew I'd be moving it a few years after construction, has worked well.
The pier is about 210mm diameter, 12mm steel pipe. Same above and below. The top half is filled with sand so reduce high frequency vibrations. The top has an adjustable plate
I don't have any problem with vibrations or movement, I'd consider anything stronger excessive. The vibrations in my setup are entirely relating to the telescope's mount and wedge, not the solid lump of steel/concrete it's mounted on :-)
I would consider concrete instead of steel, you have absolutely no concern of vibration then, providing it's big enough.
Tips:
- get the height right
- make sure you don't have rock where you want to put it (may alter your design)
- give it lots of footings
- seperate from the rest of your observatory floor
- consider wiring conduit up the centre of the pier
- consider attach points for hooks etc for controllers, mini shelves, whatever.
- don't go overboard, we don't want the earth tipping on it's side because of a 100 tone block of concrete
Pics of mine:
http://www.rogergroom.com/rogergroom...y.jsp?Item=218
Roger.
Help, I cannot handle looking at things I cannot Have....................striker, you must be ready to sell yours, $5 ok!
