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Mass mass and more mass

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#1 VVObserve

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Posted 26 October 2020 - 11:17 PM

In my quest toward a steady mount I am adding mass to the grounded side of the lever arm I call a mount.

 

After digging out around the 10 inch diameter concrete pier I have buried4 feet deep into the clay along  the last ridge before the escarpment onto the Appalachian plateau in central Pennsylvania, quaintly spelled Centre County PA.  

My observatory is sited on a shale deposit overlain with quite a few feet of rocks and clay from the last Ice Age...not the best foundation for a steady mount.

So I poured about 1000 ponds of concrete to mass up the pier.

Seems to have worked and I am ready to mount my 8.25 inch f/29 refractor on my Byers 812.

 

 


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#2 Tyson M

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Posted 27 October 2020 - 12:05 AM

In my quest toward a steady mount I am adding mass to the grounded side of the lever arm I call a mount.

 

After digging out around the 10 inch diameter concrete pier I have buried4 feet deep into the clay along  the last ridge before the escarpment onto the Appalachian plateau in central Pennsylvania, quaintly spelled Centre County PA.  

My observatory is sited on a shale deposit overlain with quite a few feet of rocks and clay from the last Ice Age...not the best foundation for a steady mount.

So I poured about 1000 ponds of concrete to mass up the pier.

Seems to have worked and I am ready to mount my 8.25 inch f/29 refractor on my Byers 812.

Looking forward to see the final set up of this! 



#3 PirateMike

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Posted 27 October 2020 - 12:35 AM

This sounds like a project is just underway, but....

 

If there aren't any photos... it never happened! tongue2.gif

 

Photos would be nice. Please. flowerred.gif

 

 

Miguel   8-)

 

 

.


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#4 csauer52

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Posted 27 October 2020 - 12:51 AM

Whoa!!!  f/29???

 

Pics please!


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#5 luxo II

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Posted 27 October 2020 - 12:52 AM

my 8.25 inch f/29 refractor on my Byers 812.

f/29 ?!? C'mon, stop teasing, show us the pics !


Edited by luxo II, 27 October 2020 - 12:52 AM.

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#6 Waldemar

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Posted 27 October 2020 - 03:46 AM

 

my 8.25 inch f/29 refractor on my Byers 812.

An almost 6 meters focal length refractor?.... wow...  I would love to see that one.
Are you sure just 1000 pounds of concrete around your 10" pier will manage that beast???



#7 VVObserve

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Posted 29 October 2020 - 04:24 PM

I recently added significant mass to my concrete telescope pier to reduce sway.
I have a 10 inch concrete pier placed on a footer 4 feet deep in the ground, however The pier was not stable enough...I was having too much sway.
To reduce the sway I dug down to the footer and filled the hole with more concrete to about a foot above the ground surface and also poured more concrete around the pier to increase the pier diameter and add mass.
I have added over 1000 pounds to the pier and the sway is much reduced.

The concrete pier is topped with a 4 foot long 8 inch diameter steel pier with a Byers 812 Mount attached with an adapter plate.
I will be attaching my ATM refractor telescope soon for mostly visual use but some photo work too.

 

Folded refractor in progress
IMG 3216
Bulked up pier
bulked up pier
Byers 812
Byers 812 and ATM folded refractor

 


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#8 Neptune

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Posted 29 October 2020 - 04:55 PM

Nicely done.  I have had to 'redo' a pier or two in my time because of this exact same problem.



#9 Sacred Heart

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Posted 29 October 2020 - 05:10 PM

You, poured concrete around concrete.  What did you use to make the new concrete adhere to the old concrete??  Also, how much weight is going on top of the concrete pier??   Mount, scope, everything.  Also,  what is the OD of the pier with the new concrete added??   Last but not least,  how high is the top of the pier from its base at ground level??

                  Joe



#10 VVObserve

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Posted 29 October 2020 - 06:30 PM

You, poured concrete around concrete.  What did you use to make the new concrete adhere to the old concrete??  Also, how much weight is going on top of the concrete pier??   Mount, scope, everything.  Also,  what is the OD of the pier with the new concrete added??   Last but not least,  how high is the top of the pier from its base at ground level??

                  Joe

I installed rebar to stabilize the new concrete so adhesive was not needed.  The original pier is encased in high strength concrete.

As far as weight...good question and I do not have an accurate answer.

The scope weighs close to 100 pounds + 100 pounds of counter weight + weight of Byers 812 here I am guessing about 60 pounds + steel pier about 40 pounds comes to about 300 pounds on the concrete pier.

Diameter of pier with new concrete is staggered from about 36 inches to 10 inches.  So I now have a pier base 4 feet deep in the ground and 36 inches in diameter, next section is 30 inches in diameter and about 2 feet in height, then a section 16 inches in diameter and 2 feet in height and finally a section 10 inches in diameter and about 1 1/2 feet in height.  Looks kind of like a layer cake.

The 8 inch steel pier is 3 feet in length and bolted to the concrete pier with 12 inch steel lag bolts set in the concrete pier. 

Height of pier including the steel section is about 8 feet from ground level.  I am estimating these dimensions.

Will this enable a calculation of some sort?

 

My enhanced pier seems pretty stable and is a huge improvement over my original pier.

I had used the original pier to mount my 16 inch Cave Astrola reflector for years with very satisfactory tracking for visual use, but the pier was not up to handling my folded refractor scope.

 

Lesson I learned...the pier must be massive.



#11 Sacred Heart

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Posted 29 October 2020 - 08:04 PM

I'd say you pretty much have it.  No calculations here.  

    You pyramid the concrete, which is good.  The only thing that I do, really do not know if it makes a difference or not, is, before pouring new concrete,  hammer in the sides of the dirt walls rebar or steel pipe to anchor the concrete to the ground.   Bottom line..as long as it works. 

 

  I had a pier once, many moons ago.  Had to set up and tear down every night. My pier was 2' in the ground and 4' above ground. Surrounded by a 16' x 16' x 3.5" concrete pad.  Setting up a Paramount ME and a C14 quickly became a young man's game.  Tore that down, now I cart the paramount ME and C14 to a 4' x 4' concrete pad.  Everything is permanently mounted on a Parallax portable pier. Acme threaded rod are my adjustments to the legs, used to raise and lower mount on or off the steel cart.

                  Good luck with your set up,   Joe



#12 Waldemar

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Posted 30 October 2020 - 02:02 AM

I'd say you pretty much have it.  No calculations here.  

    You pyramid the concrete, which is good.  The only thing that I do, really do not know if it makes a difference or not, is, before pouring new concrete,  hammer in the sides of the dirt walls rebar or steel pipe to anchor the concrete to the ground.   Bottom line..as long as it works. 

 

                  Good luck with your set up,   Joe

Hi Sacred Heart,

 

I understood that a steel contact between the concrete pier and the ground will make the steel rust because of the water content in the soil and since rust takes more volume than steel, through time the concrete will crack. Just like the roots of a tree will crack a rock.

I assume that it will take some time though...
It was my idea too to do a thing like that, but I was strongly advised against it by people who are in the concrete business.

 

VVObserve: What a cool project! Thanks for sharing.

 

CS,

Waldemar


Edited by Waldemar, 30 October 2020 - 02:07 AM.



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