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Here’s a cutaway view of my telescope’s 3D printed bases to hold rods in place. The rods go into the giant cylinders, but how do you stop them from slipping out? Insert a nut in on one side of the hole, and then screw it in from the other side. The cut in the top means the entire piece bends to hold the rod in tightly! This is so annoying to design because my rods are so close together you need to make sure that the cutaway for the nuts and screws don’t accidentally cut a hole in the wall of the places where the rods go.
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| 299 words
I took my new wooden-dowel telescope mount for a spin, and got pictures of Jupiter and Saturn with my high-power eyepiece!
I took many pictures, and a few videos. I also figured out how to control the shutter speed on my phone’s camera, and got many photos at 1/40s shutter speed. Using a smaller shutter speed takes the planets from blinding white blurs to circular colored blurs, I assume because it lets in less light.
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| 52 words
It’s still sturdy, but wobbles when I hit it. I think it might be the springiness of the wooden dowels that’s causing the motion. I could try adding two more struts and seeing if it works but I don’t really want to. It’s also very colorful now.
Time for EMT, I guess!
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Last telescope update I finished mount v2 and was stuck because it wobbled. One way to try again is to make the rods out of metal EMT instead of wooden dowels. I bought a hacksaw and spent a while hacksawing my EMT to the right length before learning there were specific pipe cutting tools that were far easier to use. Oops! I’ll also need to redesign my mount to use the larger 0.
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Update: I’ve learned about the existence of EMT conduit, which is steel so it’s much stiffer, cuttable with a handsaw, and most importantly way cheaper than the aluminum tubes I bought before!
The downside is it’s sized in nominal diameter, which means lying. The size “1/2 in” has an outer diameter of 0.706 in. But I’ve faced nominal diameter before and this time I’m prepared. Let’s try this.
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It didn’t work. The main type of wiggling I was trying to stop is the top part twisting around the z axis compared to the bottom part. This new mount stood up well, but if I placed the telescope on the mount and gave it a sideways nudge, the telescope would wiggle from side to side at a period of about 1/4 s. It does seem less wobbly than my previous square mount, but it’s still pretty wobbly.
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| 1 min
| 38 words
Starting to build telescope mount v2! I’m using 0.5in rods, and v1 had holes 0.52in wide. This one has holes 0.51in wide, and that was a mistake, it made getting the rods in there so much more annoying.
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I was unsure about how to model this part to make it non-wobbly so I looked up and watched a full lecture from MIT OCW about vibration reduction. it didn’t really help but now I understand that when you bend a stick, the outer part expands and the inner part shrinks and so by making bigger areas farther from the bending (weird) you can resist shrinking and growing a bit more.
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