Pier design

[The_bluester (Paul)]

Inspired by the other "Permission granted" thread in here.

I pretty much have a free hand in being allowed to put in a pier, all I have to do is decide where to put it. I would probably have no issues getting a roll off shed past the minister for planning as well.

My question is a bit more scope specific. I have the CPC925 and I observe primarily visually. The ALT/AZ setup is very good for visual and I am aiming to keep it that way, even if I install a pier. Being able to just walk up with the scope, plonk it down, do up three bolts and be mounted up ready to go has too much appeal to loose, but I want to be able to retain the factory tripod too for observation away from home so remounting the scope is not an option.

I have been keeping my eye on the trader section here and elsewhere to see if I can pick up a secondhand tripod to remove the mounting plate and use it on top of a pier but no luck so far.

Has anyone seen any drawings/specs on the CPC tripod top plate? If I can manage to get a pier plate made that allows the same drop on/rotate until it drops into place/do up bolts simplicity I would be very happy. It would also allow for the use of the factory Celestron wedge if I decided in the future that longer exposure photography than is practical in ALT/AZ configuration is the go.

Has anyone else had success in pier mounting a CPC Celestron without major mods?

[jenchris (Jennifer)]

Brumby, If you have a welder and some steel pipe of suitable dimension, then a steel one is indicated.
If you have a wheelbarrow and a shovel, I guess a concrete one would suit - cement would never be suitable - you need the gravel and reo for strength.

[Marke (Mark)]

You could try here www.pierplates.com although not cheap they are very well made.

[The_bluester (Paul)]

Quite tempting Mark. the only thing I can see that they have not replicated is the drop in cutouts that make lining the scope up easy. That would not be a major problem, it just would make putting the scope on just a little more fiddly as you would have to rotate the scope on the pier plate with one hand while holding the captive bolt up against the base of the mount with the other to feel when you had it lined up. The chance of getting the scope ot fall off while doing it would also be higher but not very likely as they are pretty well balanced.

I will have to have a good look, it is probably cheaper than I have any liklyhood of getting a secondhand tripod for to cannibalise, and then I have to wait for one to come up (Not in 12 months so far while I have been watching)

[Marke (Mark)]

Paul send them an email maybe they have a solution but just not on the web site .

[Vega1 (Greg)]

I just had a steel pier made locally which is 1 metre high with 165mm diameter and 5mm thick pipe.
With 25cm bottom plate/10mm thick.
Top two plates are 40cm x 25cm/10mm thick which can be levelled and rotated easily.
Extremely strong and looks great. Cost me $450 brand new.

[frolinmod]

I suspect you'll always save money and obtain a far superior pier by shopping local steel yards for scrap steel pipe and plate, then having a local welder fabricate your pier. When you buy steel at a steel yard you pay by the pound at the current steel commodity (i.e., rock bottom) price.

[Poita (Peter)]

Pardon my ignorance, but is there any reason for using cylinders over I-Beam type shapes for the pier?
The reason I ask is I have access to lengths of Universal Columns, and was wondering if it was suitable, once you weld on some gussets?
This sort of thing.
http://www.metalmates.com.au/html/uc.pdf

[Marke (Mark)]

Nothing wrong with using I beam its just easier to find pipe or box section.
Also pipe requires a lot less welding , can be a bit fidely welding your plates
on I-beam compared to a simple shape , other then that its just as stable.

[Poita (Peter)]

Good to know, welding is no problem and I get 2m off cuts of universal column pretty regularly, so it it easier for me to find than pipe.

[jenchris (Jennifer)]

I beam is more subject to twist - a lot more

[Poita (Peter)]

This is what I am unsure of. With the tiny loads being placed on a 12mm thick I-beam would you conceivably get any twisting at all? The Universal column beams are always straight, the pipe always seems to have a bit of a bend in it.
Can anyone verify how much an ibeam would twist or flex under the kind of loads we are talking about (eg EQ6 with a 10" SCT)
Genuine question, I have no idea of the answer.

[Marke (Mark)]

I do know its stiffer than pipe in lateral flexion where all your stresses would be , there would be little twisting and it would take a hell of a lot to twist a big I-beam . If your worried just weld a few braces along it to resist the twist