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Please help: Pier extension for Rob Miller Tri36M

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#1 urassner

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Posted 04 September 2013 - 03:58 PM

The first part of my new to me AP900GTO has arrived: Rob Miller Tri36M. It is absolutely gorgeous. It is ridiculously light yet seems very sturdy (have not mounted the AP900 on it yet - it will arrive next week).
Here is my question: I have a 6 inch f9 refractor which is 50 inches long with the focuser racked in, so the height of the tripod is a little too short for objects close to the zenith. Since Rob Miller does not seem to make these anymore, does anyone know where I could get a pier extension that will fit. Astrophysics has one for their 6 inch diameter eagle pier, but not for the 8 inch pier for the AP 900/1100 mount. Finding a used one would be great, but the chances might be slim.

Thank you for any thoughts or suggestions.

#2 Rebel3

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Posted 05 September 2013 - 02:14 PM

Try the Software Bisque Pyramid Extension Tube. I read somewhere that Rob licensed his design to SB and the tripods are essentially identical. Hopefully someone can verify.

#3 urassner

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Posted 05 September 2013 - 03:03 PM

Rebel3, thank you for your suggestion. I looked up the pyramid extension tubes and they use a different system than Rob Miller. The pyramid extension tube is attached by a center bolt going from the square top plate to the circular top plate.
At the Rob Miller TRI36M the extension is secured with 6 small hex screws as seen in a wonderful review of the Tri36M by Richard Keppler.

The similarities in the basic design of the Rob Miller and the Pyramid tripod are striking however; so I would not be surprised if the design was licensed.

#4 M13 Observer

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Posted 05 September 2013 - 03:45 PM

Rebel3, thank you for your suggestion. I looked up the pyramid extension tubes and they use a different system than Rob Miller. The pyramid extension tube is attached by a center bolt going from the square top plate to the circular top plate.
At the Rob Miller TRI36M the extension is secured with 6 small hex screws as seen in a wonderful review of the Tri36M by Richard Keppler.

The similarities in the basic design of the Rob Miller and the Pyramid tripod are striking however; so I would not be surprised if the design was licensed.


The Pyramid tripod definitely has Rob Miller's fingerprints all over it. You are absolutely correct though. The two top plate systems are completely different and totally incompatible with one another. I too wish I could contact Rob. I have been kicking myself for quite some time that I didn't get a TRI36H when he offered it to me. Silly me, I thought I would be able to pick it up later, when I needed it. Doh!

#5 M13 Observer

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Posted 05 September 2013 - 04:05 PM

The first part of my new to me AP900GTO has arrived: Rob Miller Tri36M. It is absolutely gorgeous. It is ridiculously light yet seems very sturdy (have not mounted the AP900 on it yet - it will arrive next week).


You will love both the tripod and the mount. It is sturdy and a great fit with the AP900 and has been my workhorse setup for a couple of years. I recently reduced my mount stable and sold off my beloved 900. Not to fear, I still have a Mach1GTO with an AP1100 for portable "heavy" use on order.

Unfortunately it seems you will have to live without the extensions or you will need to find a machine shop to make something to fit. It probably won't be inexpensive. Custom machining never is, and so saying, I'll probably be looking for someone to do some expensive work to make a lightweight adapter to fit the new AP1100 to my TRI36M.

#6 urassner

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Posted 05 September 2013 - 06:36 PM

Thank you for your input M13 Observer. I will be getting some information about custom machining. But I think you are correct: It will be expensive. I found one source for 9 inch outer diameter 6061 T6 aluminum tubing (0.5 inch wall thickness). ! foot is about $260, without any machining. 1 linear foot weights 15.7 lbs.

The tripod is amazing. After I had set it up I just could not resist and sat down on the top plate (I weight 170 lbs). Nothing. No bend, no give no wiggle. Stunning.

#7 korborh

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Posted 05 September 2013 - 09:30 PM

When I was first looking at Rob's original Astromart listing for these I was skeptical. After receiving it I was stunned too. It is clearly work of a machining genius.

#8 orlyandico

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Posted 05 September 2013 - 11:54 PM

well.. I also regret not buying an L when he offered one to me. kicking myself for that.

But in terms of engineering, how could one doubt the designer of the AP900 and Paramount ME? :)






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