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Pipe Mount

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#1 asaint

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Posted 20 February 2009 - 11:30 AM

Pipe Mount

#2 StarStuff1

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Posted 20 February 2009 - 04:03 PM

Way back in 1980 I checked out a scope for sale by a local planetarium director. It would be my first real telescope as an adult. It was an 8-in f/6 newt with 2 eyepieces and a 6x30 finder. The scope was very attractively priced but there was no mount. I had looked at a few ads for mounts and knew I could not afford an eq mount big enough to hold such a "large" telescope so I was hesitant to complete the deal. He said "Oh you can make a mount out of pipe fittings that will work and be inexpensive". I though he was kidding until she showed me the chapter in Sam Brown's "All About Telescopes" that described quite a variety of pipe mounts. I bought the scope and made a pipe eq out of 2-inch pipe and fittings. For a "tripod" I bought a surplus/discounted bench grinder stand for a very low price.

The telescope and mount worked great. The 4-legged tripod proved to be a problem as it seemed one leg was always not securely set on the ground. Eventually I sold/traded the scope and converted the tool stand to it's properly designed use.

I kept the mount though and later used it with a 114mm f/12.5 refractor.

Since then I have made a couple more pipe mounts including this one http://www.cloudynig...php?item_id=415

Thanks, Mr Wang, for adding more exposure to the all too often overlooked pipe mount.

#3 Mike Lynch

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Posted 20 February 2009 - 04:34 PM

"If I can observe for hours without fussing over my equipment, then the equipment is good."

What else can you ask for?

Mike

#4 mathteacher

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Posted 20 February 2009 - 04:35 PM

Starstuff, I referred to your article when I made my mount, so thank YOU. :bow:

#5 StarStuff1

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Posted 21 February 2009 - 07:14 PM

Hey Mr Wang,

I like your idea of the string to keep the azimuth bearing from unthreading znd letting the OTA crash. That was one thing that really worried me especially when I had the long refractor pipe mounted. Every time I took it out I would screw it all the way in and hope I did not do too many "walk- arounds". Your solution is clever.

#6 mathteacher

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Posted 21 February 2009 - 07:32 PM

Thank you, sir. I love ropes and knots. If I have a problem, I ask: how can string help me?

I spent 3 hours with the pipe mount and the 6" refractor last night. At 200x the mount worked well for lining up drift-throughs of Saturn. At 240x, stiction on the altitude bearing made it tougher to put Saturn in the best place at the edge of the EP. I may go back and lap the Alt. threads some more so more threads are engaged to evenly distribute the weight. Take care.

#7 mathteacher

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Posted 22 February 2009 - 01:05 PM

Here is another CNer's pipe mount. LINK

#8 John Hoare

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Posted 27 February 2009 - 06:40 AM

An excellent article Mr Wang, and a timely reminder that when times are tight - or if we want to - we can build the equipment we need for this hobby.

The pipe mount may not have the same finish as my Giro II but it certainly looks equally sturdy and practical.

#9 proud uncle

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Posted 16 March 2009 - 01:18 PM

Mr. Wang, I just re-read your article, and have a few observations/questions.

For easily removing the 1/2" nipple for ease in transport, do you suggest also lapping this nipple's threads at the adapter?

How easy would it be to mount this directly to a surveyor's tripod -- by screwing Flange B directly to the tripod? If yes, why not lap the 2" nipple B threads at the 2" flange B instead of at the T? Then the azimuth motion would be around that point instead, and the string should still work.

Please excuse my DIY naivity, but what is the "spring clamp" you use for securing the free weights?

For smaller scopes, such as an Orion 80st or 100 mm f/6 achro, would it work to use 1" nipples, T, and flanges, instead of 2"?

Thanks for the great ideas!

#10 mathteacher

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Posted 16 March 2009 - 02:19 PM

For easily removing the 1/2" nipple for ease in transport, do you suggest also lapping this nipple's threads at the adapter?


No, I don't think that is necessary. Just hand tighten and hand loosen. I haven't fiddled with the CW bar since I made the mount. It's held firm. I may take it apart this weekend for the first time.

How easy would it be to mount this directly to a surveyor's tripod -- by screwing Flange B directly to the tripod? If yes, why not lap the 2" nipple B threads at the 2" flange B instead of at the T? Then the azimuth motion would be around that point instead, and the string should still work.


Good question. I lapped the threads at the T because it is closest to the telescope. I think the closer threads to the load you use, the fewer forces and torques the bearing has to deal with. If you lap the threads at the base flange, it may still work, but I don't like that big moment arm of the foot long 2" nipple. Theoretically there should be no lateral force on the scope (only gravity pulling down), so it shouldn't be a problem. But, as a design principle, keep everything as close to the scope as possible.

Please excuse my DIY naivity, but what is the "spring clamp" you use for securing the free weights?


It's just a clamp you buy at the hardware store. It's just a detent to keep the weights from accidentally sliding off. It doesn't need to be very strong.

For smaller scopes, such as an Orion 80st or 100 mm f/6 achro, would it work to use 1" nipples, T, and flanges, instead of 2"?


I would use 1.5" parts for a 100mm and 1" parts for an ST80. I'm thinking of making one for my ST80 using an 90 degree elbow, no counterweight. It would be just 2 flanges and an elbow.

Thanks for your questions

#11 mathteacher

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Posted 31 March 2009 - 08:47 PM

FWIW, I re-lapped the altitude threads recently. The amount of effort increases exponentially towards the end. I only managed to engage one more turn of the threads, but it was worth it. I was able to track Saturn at 300x without much hassle.

#12 mathteacher

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Posted 04 June 2009 - 10:31 PM

This is a pipe mount I made out of 1" pipe fittings for my ST80. I forewent the counterweight, thinking the ST80 is very lightweight. A couple of problems popped up when using this mount in practice. The short tube does not allow for proper balancing of the OTA (it is tail heavy with diagonal and EP). Luckily, the dovetail plate has threaded holes that allow me to attach the OTA further forward of the axis of rotation. Secondly, the shorter tube, and the use of the 90 degree elbow made the scope hard to point. The motion is jerky because you lack a long enough moment arm to overcome stiction in the threads (lack of counterweight also affects azimuth axis). Adding the pan handle improves the altitude axis. Sometimes using two hands helps smooth out the azimuth motion. This mount is fine at 100x, which is near the top end for the ST80 anyway. At 200x aiming becomes a chore. The pipe mount I wrote about in the article is definitely more effective. For a short achro like the ST80, this is still a serviceable mount.

Attached Thumbnails

  • 3146548-ST80pipemountCU.jpg


#13 Raven911

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Posted 05 June 2009 - 09:43 AM

I used to use a big EQ made of pipe for my old AR-6 refractor. It was just about perfect for it. Of all the mounts I have ever used, it balanced the best out of them.

All it needed was tracking.


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