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Pier-tech adjustable piers -- opinions?

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#1 jazle

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Posted 13 December 2013 - 03:40 PM

Looking for feedback on the pier-tech piers. They claim they maintain polar alignment.

With my permanent pier made out of a 12" steel pipe, I know that every night I can go out, tell the mount to slew to a target, and it will within a dozen arc-minutes or so. No need to plate solve to find the target except to land it perfectly in center on the next slew. Only complaint is that I have exactly one way to home the scope with about an inch of roof clearance. No way to add a permanent piggy-back camera, for example, without chopping the pier down and re-welding it.

I'm skeptical how an adjustable pier could maintain the same precision. But, if it can, it would be a great addition to my observatory.

Based on the load capacities, I'd have to go up to the model 3 since I have about 60# of equipment, 90# of counterweights, the CGE-Pro mount (75#?), and any adapter plates.

Thanks in advance for any feedback!

#2 Footbag

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Posted 13 December 2013 - 03:41 PM

Just the other day, someone posted a place that was selling the adjustable piers at huge discounts. I think they were overstock or something. If you can find the thread, it may be worth a look.

#3 frolinmod

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Posted 13 December 2013 - 04:11 PM

With my permanent pier made out of a 12" steel pipe, I know that every night I can go out, tell the mount to slew to a target, and it will within a dozen arc-minutes or so.

I hope you mean arc-seconds.

I too am skeptical of how well these furniture lifts can maintain polar alignment.

#4 Raginar

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Posted 13 December 2013 - 05:10 PM

The one I bought seems to work pretty good. I don't have it in the obs yet; it'll be a spring install I think. They're exactly the same hardware that Pier tech uses.

I paid 300 bucks for mine and I still have to get a relay for my roof controller to make it raise and lower automatically. The thread is in the DIY sub forum, just search for linak DL2.

#5 BYoesle

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Posted 13 December 2013 - 05:44 PM

See the following links:

http://www.cloudynig...&Board=atm&N...

http://www.cloudynig...rd=lxd55&amp...

#6 Jim Chung

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Posted 13 December 2013 - 06:37 PM

Don't be skeptical. With my Piertech clone fully extended I can still image with 10 minute subexposures at nearly 3000 mm focal length with my 8" refractor. Clearly polar alignment is not an issue.

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#7 Raginar

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Posted 13 December 2013 - 08:12 PM

Best proof I've seen :) I'm following Jim's plans.

#8 Moabite

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Posted 14 December 2013 - 09:28 AM

I've had the Pier-Tech 2 since 2007...love it. I've noticed no shift in alignment when raising or lowering the pier. Until last summer, a 12" LX200 was mounted on it...now the 12" LX600. I see that they have increased substantially in price though. I paid $1500 direct from Pier Tech.

#9 Scott Busby

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Posted 14 December 2013 - 10:12 AM

I also use a PierTech II in my 10' domed observatory. I absolutely love it. I have no issues with maintaining polar alignment from full extension to full compression. I usually mount a Tak EM400 with either a Tak TOA150 or Mewlon 250 with an assortment of guide scopes, finders and cameras. No issues whatsoever -- I love it.

#10 jazle

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Posted 16 December 2013 - 04:08 PM

Thanks for the feedback and links, folks!

Has anyone seen any swaying movements created by light winds, hanging cables, etc... Especially oscillations since it doesn't have any way to dampen itself? My 12" steel pier full of sand isn't going anywhere. I can lean all of my 250#'s of bodyweight where it sits 4' off the top of the concrete column and you won't see any movement from a live feed. And if you give it a good whack with a shoe, it doesn't ring and only slightly jars the stars for a brief moment.

When I see the Linak columns and with my experience nesting two pieces of pipe inside each other, that you just have some play where they sit inside each other in order for them to be able to slide past. And since they are one large thin-walled hollow column, they seem they would also be prone to ringing.

Now having said that, I actually spend my day working at a Linak-powered adjustable desk. The thing is a tank. If I try to move the table top, it barely budges. And it is only sitting on top of some minimally cross-braced pair of columns.

Jim, I looked with great interest at your solution. I was tempted to call up your source and order a column of my own, but I fully expect I'll be pushing every Newton of a single column's capacity.

But that got me researching and I found some other Linak columns on ebay that are designed for the ergo tables like I have at work that have the built-in sensors to allow parallel operation with a Linak controller. One person is selling some really close to me so I sent them a message to see if we can come up with a deal on a few of them.

I figure I could either mount three or four of them between two plates with a welded cross member and that would resist quite a bit of torque along the various moments, provide plenty of stability in keeping the top plate level, and allow for plenty of lifting capacity (3x700N = 472# and 4x700N = 630#)

Jason

#11 Odell

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Posted 04 January 2014 - 11:24 AM

Jason,

I bought mine from Pier Tech about two years ago. Mine has the ten inch extension and tripod legs for portability. I've had mine out at a dark site with a 6" f/8 refractor mounted with a light breeze blowing and the thing didn't move one iota. It holds polar alignment through the entire travel and has been reliable as hell through my ownership. Vito is pretty proud of his work price wise, but I haven't regretted the purchase.

Ian

#12 Skunky

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Posted 04 January 2014 - 07:40 PM

I have a full PT2 setup with the pier caddy (purchased form pier-tech). I also have an older PT3 single column (used market). My PT2 was perm mounted with a Cge-Pro and side by side. It worked well. I have since moved the PT2 to the pier caddy and now use the PT3 with a AP1600 in a SBS setup. I have noticed that the PT3 can rock back and forth as mentioned in other older threads on the forums. I believe turning it over can help the issue but a custom weld job around the base hopefully can fix the issue.. it's not an issue really.

If you can get it that cheap, for usre go for it... just fyi.. Vito, @ pier-tech, customer service sux.

#13 Raginar

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Posted 05 January 2014 - 12:03 PM

Jason,

Mine isn't in the obs yet, but my guess is its as rock solide as you bolt it. My other guess is that it probably has some vibrations but that they dampen out pretty quickly.

#14 CarolG

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Posted 05 January 2014 - 05:52 PM

I have an older model PT3 (single column) with an AP 1600 and C14 on it. I noticed some rocking, but realized that when I was leveling the pier using the adjustable bolt system on the base, I had not tightened up the bolts properly. Now it is pretty solid, but when fully extended, it does have some minor problems with vibrations, but it is so minor that it has not been a problem.

#15 BYoesle

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Posted 05 January 2014 - 08:13 PM

As documented here http://www.dd1us.de/...a pier for%2...
and explicitly in their patent, Pier Tech uses Linak lifting columns for their adjustable height piers, and adds an upper and/or lower mounting plate.

You can get the older version of the Pier Tech -- a 270 lbs (1200 N) capacity Linak DL2 lifting column -- from Stone Dimensions ( http://www.stonedimensions.com ) , and it cost only $250. For this price, you will not get the top adapter plate that comes with the PT2 ($2500), but such an adapter plate would be fairly easily made.

Here’s the one I purchased, and it includes everything you need including the control box, handset, and cables. While I haven’t installed it yet, it seems quite robust when fully raised.

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#16 BYoesle

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Posted 05 January 2014 - 08:15 PM

Based on the load capacities, I'd have to go up to the model 3 since I have about 60# of equipment, 90# of counterweights, the CGE-Pro mount (75#?), and any adapter plates.



Since Linak does not sell directly to the public, I had Steve Raymonds at Stone Dimensions order me the newer DL2 columns as used in the PT3. However, I opted for a slightly different DL2 version (1500 Newtons lifting capacity), as the 2500 N DL2's with a 500 mm stroke length used by PT required a waiver due to Linak's concerns it was “outside our specifications (normal max stroke on a 6mm [spindle pitch] DL2 is 300mm) and the primary overheating of the brake and stability of the actuator.”

So rather than the 1100 lbs. (2500 N x 2) capacity of the PT3 ($3800), the 'clone' version I have has a lifting capacity of 675 lbs. (1500 x 2 = 3000 N -- but is rated and warranted for the full 500 mm stroke length), which is more than adequate for my purposes ~ $1400 (the price for the pair through Stone Dimensions for either version of the DL2's was the same).

With regard to Skunky's concerns about customer service from PT: Steve at Stone Dimension's has given me the absolute best customer service I have encountered. I can't recommend him and SD highly enough. :bow:

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#17 jazle

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Posted 06 January 2014 - 01:49 PM

Thanks, Bob!

Will be interested to hear how your PT3 clone works out.

I'm leaning towards a three-actuator lift with three actuators spaced 120-degrees around a 12" or so diameter circle. Just need to find the actuators and controllers for cheap. Fabricating/Welding will not be a problem for me, just getting the components. Doesn't help that Christmas tapped me out on the free cash flow!

#18 jazle

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Posted 07 January 2014 - 02:22 PM

Well, someone was selling some DL4 columns on ebay for $39 each. I got them to sell me three for $33 each yesterday.

Someone else was selling a 3-port CBD4 controller for $139 with wires, but I hesitated too long and it was sold by this morning. I've emailed Steve at Stone Dimensions to see what he can do.

Bob, have you looked into what the control panel would need for automation? I'm assuming I could buy the cheapest panel on ebay (about $28), disassemble it, and put two relays in place of the up/down buttons.

I plan to also place a limit switch in the furthest down position on the pier that is tied into the disable of the roof controller -- so you can't move the roof (open or close) without the telescope being lowered.

#19 Raginar

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Posted 07 January 2014 - 08:50 PM

Jason, I dunno what your automation routine is but my Foster controller just requires a special relay to control it. Roof opens.. pier goes up. Roof gets the 'close' command, it waits until the pier drops, and roof closes.

Pretty smooth.

#20 jazle

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Posted 08 January 2014 - 01:31 PM

Mine is homemade. No microcontrollers to sequence the operation. I used AC-powered relays connected to a network power switch.

I thought about going the microcontroller route -- I've built a few embedded devices in my profession and as a hobby -- but decided to go the more low-tech route to reduce the number of failure points.

Because I have limit switches on the roof for both open and closed positions, though, I'll also have to add a lockout on the pier raise condition to require the roof to be fully opened as well.
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#21 Raginar

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Posted 08 January 2014 - 07:10 PM

Again, mine just requires a special relay... from there it's a 12V signal to the relay to cause it to rise... another one to lower it. I think you could figure out how to relay that via a network power switch.

#22 Raginar

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Posted 07 May 2014 - 12:20 PM

It ended up not needing the relay. Just had to wire it up correctly to the input/output and it goes up and down without any issues.

It is rock solid, no issues with 40 lbs of counterweights, the 40 lbs of mount, and 70 lbs of gear I have on it right now. I have imaged in 10 kt winds without any issues.

I think it's a real win :)






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