I had a pier fabricated for my telescope but the final product is not rigid. A small amount of force or a bump will cause excessive movement of the telescope - think "upside-down pendulum". This is BAD FOR ASTROPHOTOGRAPHY ☹️. I need to find a way to make the pier more rigid. I realize that I can start over with a redesign, and it may come to that, but I want to see if I can save the existing pier as I already invested in its fabrication.
DETAILS:
The pier consists of a 1/4" steel plate, 10" diameter, bolted to a concrete pad. A 3" by 34" square steel tube is welded to the base plate and the mount head is welded to the tube. The mount head consists of two 1/4" steel plates, 8" diameter, separated by three 2" square tubes, 6" long. I have since added an equatorial wedge to the top of the mount. This wedge converts the telescope mount to an equatorial mount. But it added another 12" to the height of the telescope, which has exacerbated the unwanted telescope movements. The telescope assembly that sits on top of the pier weighs about 70 lbs.
As I stated I am looking for ways to increase the rigidity of the original 3" pier post.
Would bolting four 3" square tubes to an existing 3" square tube (one per side) increase rigidity? I would need to bolt vs weld because the extra tubes would cover over the bolts that mount the whole pier to the concrete base. If I weld them I can no longer remove the pier, if needed.
Does anyone have another idea that would stiffen the pier? I would appreciate any advice you may have.
Below is an image of the original design and a photograph of the current setup:
Question
Mike S
SUMMARY:
I had a pier fabricated for my telescope but the final product is not rigid. A small amount of force or a bump will cause excessive movement of the telescope - think "upside-down pendulum". This is BAD FOR ASTROPHOTOGRAPHY ☹️. I need to find a way to make the pier more rigid. I realize that I can start over with a redesign, and it may come to that, but I want to see if I can save the existing pier as I already invested in its fabrication.
DETAILS:
The pier consists of a 1/4" steel plate, 10" diameter, bolted to a concrete pad. A 3" by 34" square steel tube is welded to the base plate and the mount head is welded to the tube. The mount head consists of two 1/4" steel plates, 8" diameter, separated by three 2" square tubes, 6" long. I have since added an equatorial wedge to the top of the mount. This wedge converts the telescope mount to an equatorial mount. But it added another 12" to the height of the telescope, which has exacerbated the unwanted telescope movements. The telescope assembly that sits on top of the pier weighs about 70 lbs.
I have since found (yes, I wish I found this before I had the pier fabricated) some guidance that says I should have used a "thick" base plate and a 1/4" steel tube 8" in diameter. https://www.cloudynights.com/articles/cat/articles/how-to/pier-design-fundamentals-r1236
MY QUESTION:
As I stated I am looking for ways to increase the rigidity of the original 3" pier post.
Would bolting four 3" square tubes to an existing 3" square tube (one per side) increase rigidity? I would need to bolt vs weld because the extra tubes would cover over the bolts that mount the whole pier to the concrete base. If I weld them I can no longer remove the pier, if needed.
Does anyone have another idea that would stiffen the pier? I would appreciate any advice you may have.
Below is an image of the original design and a photograph of the current setup:
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