Adjustable pier... any idea?

[Andrew*]

I've been considering how to make a pier for my obsy.

My thoughts were that as I've got a reflector (EP way up high(sometimes!)) and a refractor (and low down), and also that i'm a lanky chap and some folk are not so tall, an adjustable height pier would be the way to go...

However, it's obvious that whatever you add to a pier it may affect the stability or alignment of it.

My idea was a great big steel pole concreted deep in the ground. Inside another steel bar with the pier head on top of that. Then some holes drilled through the pole so a pin (a big metal stick of sorts) can be stuck right through that the bar will rest on. This will stop the pier falling downwards. To stop it rattling about inside the pole, I would simply make two bolts (or four - two at the top, two lower down) that tighten onto the bar and hold it in place. The whole thing would be inside a plastic pipe of sorts (gas pipe, gutter etc.) and filled with more concrete, of course with holes for the fixing bolts to come through. For retaining polar alignment I would just have to line up two markers.

Just from the idea, I would imagine I would end up with a stable pier whether up or down. My other idea was to simply make a really tall one (6" off the ground, provided the shed roof doesn't get in the way!) and use an adjustable height footstool/ladder. But then again, would something that tall still be stable?

Does anyone have any other ideas for a height adjustable pier?

Cheers

Andrew

[Helen]

I saw one these advertised... might give you some ideas! http://www.pier-tech.com/pier-tech2_telescope_pier.htm

Helen

[Andrew*]

saw that one, Helen! It would be more than the obsy though, then there's shipping... :shock: Mind, it looks VERY nice kit and would love to have one.

Andrew

[Kaptain Klevtsov]

Due to my location Andrew...

(Definition of Yorkshireman: Similar to a person from Scotland but lacking the native generosity)

I went for two piers, a tall one and a short one. You might need two mounts, or swap the mount head from one pier to the other depending on your equipment for the night. If you're doing a viewing for several people, it also makes sense that you have more than one setup at a time.

A pier with adjustable height that doesn't need a lot of realignment after height adjustment is going to be a costly thing, more so than a second pier, so go cheap, go the two pier route.

Kaptain Klevtsov

[Andrew*]

I went for two piers, a tall one and a short one. You might need two mounts, or swap the mount head from one pier to the other depending on your equipment for the night. If you're doing a viewing for several people, it also makes sense that you have more than one setup at a time.

A pier with adjustable height that doesn't need a lot of realignment after height adjustment is going to be a costly thing, more so than a second pier, so go cheap, go the two pier route.

Interesting idea, KK.

However, unless the shed observatory will be at least 8x10 I can't see two piers going in there!

What about having a simple extension tube to sit between the pier and the mount? Would that be sturdy enough?

You see, my problem at the moment is that I simply don't understand this "stability" thing. I mean, in terms of how it's built, what's the difference between a pretty sturdy pier and really amazingly rock solid in a nublear explosion pier?

For example, people get away with fine images with a tripod sitting on grass in their back garden. That sits on soil which to quite an extent wobbles the tripod legs about when you walk within a foot of them. So a pier, sat in a tonne of concrete, and separated from the floor you stand on, surely a basic height adjustment mechanism that locks say as sturdily as the legs on your tripod (I'm not saying the same mechanism) won't affect stability that much. Especially considering that the comparitively delicate nature of simple fixtures such as tube rings or, for that matter, the tube itself, will surely let down the stability of the image far more than what it all sits on.

I hope you understand that ramble. I need to clarify this before leaping in to anything!

Cheers

Andrew

[Kaptain Klevtsov]

Your comments prompted a thought! If you folded up the tripod, then welded all three legs to a post in the ground, you could use the tripod leg adjustments to change the height of the pier. I wonder if anybody has done this?

Kaptain Klevtsov

[Andrew*]

The thought had occurred to me actually!

However, I wondered whether using that method would get the set-up high enough for the likes of me, considering that it's still too low sometimes on the tripod's full height when sitting on the ground, let alone in the ground.

cheers

Andrew

[SteelRat]

Wouldn't that depend on the height of the post in the ground Andrew?

[Andrew*]

:scratch: :sign6:

for some reason I thought the post would be submerged...

Now I'm thinking again!

cheers

Andrew

[SteelRat]

Heheheheh, me got soft head too sumtimes lots

[Andrew*]

I went for two piers, a tall one and a short one. You might need two mounts, or swap the mount head from one pier to the other depending on your equipment for the night. If you're doing a viewing for several people, it also makes sense that you have more than one setup at a time.

A pier with adjustable height that doesn't need a lot of realignment after height adjustment is going to be a costly thing, more so than a second pier, so go cheap, go the two pier route.

Interesting idea, KK.

However, unless the shed observatory will be at least 8x10 I can't see two piers going in there!

What about having a simple extension tube to sit between the pier and the mount? Would that be sturdy enough?

You see, my problem at the moment is that I simply don't understand this "stability" thing. I mean, in terms of how it's built, what's the difference between a pretty sturdy pier and really amazingly rock solid in a nublear explosion pier?

For example, people get away with fine images with a tripod sitting on grass in their back garden. That sits on soil which to quite an extent wobbles the tripod legs about when you walk within a foot of them. So a pier, sat in a tonne of concrete, and separated from the floor you stand on, surely a basic height adjustment mechanism that locks say as sturdily as the legs on your tripod (I'm not saying the same mechanism) won't affect stability that much. Especially considering that the comparitively delicate nature of simple fixtures such as tube rings or, for that matter, the tube itself, will surely let down the stability of the image far more than what it all sits on.

I hope you understand that ramble. I need to clarify this before leaping in to anything!

Does anyone have any mroe thoughts on this?

cheers

Andrew

[Kaptain Klevtsov]

The biggest issue with the height adjustment Andrew, is the need to retain polar alignment during the height adjustment. If you can't keep it aligned, you lose most of the advantage of having a pier in the first place. You might do better just using the tripod inside the shed.

Kaptain Klevtsov

[Andrew*]

KK,

I thought of that. Do you think lining up two markers wouldn't be accurate enough? Or what about having the a slot in the middle shaft and a rod in the outside shaft so that it couldn't be rotated?

Andrew

[Kaptain Klevtsov]

No mate. You need it spot on, like really spot on, if you want to do imaging with it. For visual, you'd probably get away with a big H section stuck in the concrete, and a square tube slid over the top plus some clamps.

Kaptain Klevtsov

[Andrew*]

KK

Cheers for clarification. I thought maybe if the system is pretty accurate, I could do a proper drift align afterwards when I'm planning an image. I'll probably kill myself later though...

I'll re-view the whole idea. Maybe the tripod legs idea might work...? I would imagine there would be some room for error with this idea, because the tripod head might not be completely level after adjusting.

How do you think the folk in Helen's link do it and "guarantee" a perfect polar alignment?

Andrew

[Kaptain Klevtsov]

Check these people out.

http://www.hollinapplications.co.uk/Lifting%20Aids.htm

No prices that I could find, but you could e-mail them with a specification and see what happens.

Kaptain Klevtsov

[beamish]

Perhaps the answer would be to look at it from another angle ,ie an adjustable viewing platform that can be maneuvered around the pillar ?

Karlo

sorry just seen the link- I'm sure I've come across an American who built a pier with something like that . I'll get my coat !

[Andrew*]

Perhaps the answer would be to look at it from another angle ,ie an adjustable viewing platform that can be maneuvered around the pillar ?

Karlo

sorry just seen the link- I'm sure I've come across an American who built a pier with something like that . I'll get my coat !

Thought of that too. My first thought was --- wait for it!--- a stepladder! But something a little more complex could be thought up.

Check these people out.

http://www.hollinapplications.co.uk/Lifting%20Aids.htm

No prices that I could find, but you could e-mail them with a specification and see what happens.

Will do that. KK, I appreciate you doing my research!!

Cheers

ANdrew

[Rols]

saw that one, Helen! It would be more than the obsy though, then there's shipping... :shock: Mind, it looks VERY nice kit and would love to have one.

Andrew

Price is $1975

Shipping is $500

Thank You

Vito Rotondi

President

Pier-Tech Inc.

About 2500.00 by the time its here it works out about 1-1 exchange by the time you add the taxes implied as it enters the country.

I thought 500.00 shipping cost was a little over the top!

i'm in the midst of ordering one and having it shipped privately, as to avoid 5% import and 20% vat, i have family in the location that can ship as a present. the item weighs 70 lbs so not light, they come as standard with base mounting plate.. we shall see if it can hold polar at full height i suppose....

Edited October 13, 2011 by Rols

[Nillchill]

In the Starmen TV program the other night, one guy had mounted his pillar onto a platform supported by a couple of scissor Jacks, he would then wind them up to allow up to 24 inches of extra height.

they only cost £18 each

1.5 Tonne Scissor Jack | Screwfix.com

might be an option for you

[Horwig]

My adjustable pier gives me 24 inches of lift, is powered by a 24 volt linear actuator, can easily lifts me of the ground, and gives repeatable polar alignment on my 2500mm scope.

It cost me less than 900 quid to design and build, and is really low tech. Would that answer your needs?

http://stargazerslounge.com/diy-observatories/147555-socially-acceptable-astroshed.html

Huw

Edited October 13, 2011 by Horwig

[steelfixer]

Andrew have you never seen a dentist or barbers chair?

The sort you pump up with your foot.

Can you not find a secondhand / broken one locally.

If not try a hospital trolley they have a similar arrangement as well. ( make rearly good motorcycle work benches as well)

You can concrete the base down like a conventional pier extend the top tube that the seat was fixed to and hey presto you have a pier that will go up and down with zero rotational movement.

graham

[Rols]

Page 24 of the Thomson PDF.

very interesting that the figures for end play on these Thompson telescopic lifting columns is maximum 1mm at full extension, i did also note that the TC 16 has no figure in the tech specs, i have asked the question in a mail to them and also noted that the maximum depth of any fixing to the top is 10mm a modified fixing plate would need to be made to take a wedge.

A question i would ask at this stage is what is the difference in exposure time if your mount is off by a maximum of 1mm from the original polar alignment?

[Horwig]

I finally found this article, I knew I'd seen it somewhere...

Huw

http://f1.grp.yahoofs.com/v1/EF-cTi9KpbtaFN574CmX7jLGSlhi7bhyyl6BLh02WHyQoP-nUfgw-AEkisdT_gciejeF1p61Us84KMQS2qoJ5E4xCuD_4g/telescoping%20pier.pdf

[daslolo]

I'm embarking on the same adventure.

Here is the plan:

Pier made of 2 tubes . The Host is 6" with an ID that matches the OD of the smaller tube which is a roughly 5"

Smaller tube attached 3" inside to a 12" linear actuator, these are narrow enough to fit in the 6" host tube.

There will be some leeway, this is handled by 2 screws welded to the 5". The pass through  a slit in the 6", tighten by bolted handles

 

Edited June 4, 2020 by daslolo