View Single Post
  #32  
Old 22-11-2011, 11:31 PM
bmitchell82's Avatar
bmitchell82 (Brendan)
Newtonian power! Love it!

bmitchell82 is offline
 
Join Date: Jul 2008
Location: Mandurah
Posts: 2,597
... There was a very heated debate about it hence the general tone of the blog... see ARM CHAIR EXPERTS.... S

The program I used in that analysis is Multiframe which is a structrual analysis program I use programs like that on a daily basis but understand how to actually do all the calcs manually, that would put the fear into most mortal men some of the calcs.

As for 50 KG if you are in a obs youll never get that kind of loading on it not in a blue fit as your scope is balanced and the weight is dragging though the center of gravity or the centroid of you equipment. Thats what makes me laugh most of the time when people talk about the whole pier deflecting or the vibration when you hit it or filling it with sand. Sand will only dampen the high frequency vibration (the ringing sound) itll do squat for anything else, unless somebody can bring to the table scientifically peer reviewed testing ill stand by what I have said.

Unless you are putting a massive telescope up on top. eg Paramount ME + 14"+ the deflection willl never move more than your guiding can handle and even then it will still handle it.

At the end of the day ide be more concerned about the soil that your putting your pier footing in. No bigger isn't best as soil will lift a building! if you have reactive clay be prepared to either stabilize alot of soil or just tweak your polar alignment every now and then.

One of the piers that i constructed for a friend of mine who runs a RC has it standing clear of the ground on 4x M24 threaded rod and bolts with 250 SHS. the footing measures 400 x 400 x 500 and is rock solid, the images he produces are amazing!

Ill flip the analysis though in the morning before i start work and tell you what you can expect in any case with your current section

Brendan
Reply With Quote