3D printed telescope for deep sky astrophotography

Buying and setting up a telescope is one thing, but 3D printing one from scratch is a whole other thing. It takes time, effort, and knowing how things fit together. That’s what someone decided to do, build a working 3D-printed telescope for deep-sky astrophotography. The idea was to make something that works, isn’t too expensive, and others can try too. This wasn’t just a project; it was about seeing what 3D printing can do. The guy behind it? Dave Aldrich, the guy from “Design by Dave” and “Dave Builds Stuff,” who made it happen.

3D printed telescope for deep sky astrophotography

He had worked on other astronomy projects before, including the Hadley telescope, which is a great beginner scope for those looking to get into astronomy. But the Hadley wasn’t built for long-exposure deep sky imaging. The focal length was too long, and it wasn’t rigid enough for astrophotography, which demands precise tracking. So, he set out to design something that would be the “Hadley” of astrophotography, a telescope that could be printed at home and actually produce solid images of deep space.

The design he settled on was a Newtonian reflector, but with a fixed camera mount instead of an eyepiece. That meant it wouldn’t really be great for visual astronomy, but that wasn’t the goal. The primary mirror was 114mm in diameter, with an f/3.95 focal ratio and a 450mm focal length. He sourced the mirror from eBay, though similar ones are available on AliExpress. Since he was using small image sensor cameras like the Sony IMX585, this setup provided a narrow field of view, which is great for capturing small deep sky objects but also meant guiding would be a challenge.

One of the big trade-offs with a fast Newtonian telescope is coma, an optical aberration that makes stars look stretched toward the edges of an image. To fix that, he needed a coma corrector, which was unfortunately one of the more expensive parts of the build. He went with the Sharpstar, which not only corrected coma but also slightly reduced the focal length, making it a useful addition. This cost a little over $200, which made it the single most expensive component of the whole telescope.

One of the key structural elements in the design was the use of three 15mm carbon fiber tubes to provide rigidity. Since 3D-printed plastic alone isn’t rigid enough for a telescope, these tubes acted as a backbone to align and hold the printed sections together. The tubes were bonded in place with epoxy, except for the rear tube, which was secured with set screws so the primary mirror could still be accessed for adjustments and maintenance. To make the telescope easy to mount, the top and bottom sections included flat areas with heat-set inserts for attaching a dovetail plate and a guide scope.

A big challenge in this build was the focuser. Buying a pre-made focuser would have been easier, but that would have increased the cost and weight of the telescope. He wanted to design something that could be 3D printed while still being smooth and stable enough to hold a camera without flexing. His first attempt was a rack-and-pinion draw tube system, using PTFE Bowden tubes as low-friction guides. But after several iterations, he found it tricky to get the right balance between smooth movement and rigidity.

Then he tried using helical gears, thinking they might provide a better, more compact motion. But he quickly found that the side forces from the helical gears were introducing too much friction and twisting the draw tube. So that idea got scrapped. After researching camera lens designs, he settled on a helicoid-style focuser that used a circular track and small steel ball bearings. The ball bearings reduced friction and eliminated the need for extra clearance, which had been a problem in his earlier designs. After a few test prints and some adjustments to the spacing of the bearings, he got it working well enough to move forward with printing the final parts.

For the main body of the telescope, he used a new type of filament he had recently discovered, ABS carbon fiber core filament from Siraya Tech. Unlike standard carbon fiber-filled filaments, which can sometimes weaken layer adhesion, this filament concentrated the carbon fiber in the core of the material while keeping the outer layers as pure ABS. Whether or not that actually improved strength would require proper testing, but anecdotally, the parts felt stronger and stiffer compared to plain ABS. The print quality was excellent, with minimal warping, which was crucial for keeping everything aligned properly.

Once all the major components were printed, he started assembling the telescope. The focuser was mounted to the front ring of the tube using hex pegs and epoxy. The carbon fiber tubes were carefully aligned and bonded into place, making sure they provided a solid structure. Before assembling everything, he also painted the inside of the tube sections with matte black spray paint to cut down on internal reflections.

With the structure complete, it was time to install the optics. The primary mirror was attached to the mirror cell with three drops of silicone adhesive. The secondary mirror was glued to its holder in a similar way, but first, he made sure the central mounting screw was secured in place with a bit of silicone, so it wouldn’t rotate while adjusting the mirror alignment. The secondary mirror was supported by three carbon fiber vane supports, which were also epoxied into place.

Once everything was assembled, he took the telescope out for an initial test. Since dialing in the focus at night can be difficult, he set up in a Lowe’s parking lot during the daytime, using distant mountains to get a rough focus. Once he confirmed that the focuser had enough range to bring objects into sharp focus, he moved on to mounting the telescope for its first real test under the stars.

His first night of testing was live-streamed, and it was a bit of an adventure. There were plenty of small issues to troubleshoot, things like adjusting the collimation, dialing in the guiding, and making sure the mount was tracking well enough for long exposures. Even with those challenges, he was able to capture some early test images. The stars weren’t perfectly round due to some tracking inaccuracies, but he was still able to get enough usable data to produce an image of the Crab Nebula.

After that first test, he went back and made further refinements. One issue was that the focuser draw tube had a bit of play, causing the camera to wiggle slightly. To fix this, he reprinted it slightly oversized and carefully sanded the grooves to create a snug but smooth fit. With that fixed, he took the telescope out for another round of imaging in a dark sky location with some friends.

Even though his mount wasn’t tracking as accurately as he would have liked, he still managed to capture some great deep sky images. One of his favorites was M78, a reflection nebula in Orion, which showed off its signature blue glow and dark dust lanes. He also imaged the Leo Triplet, a group of three galaxies in the constellation Leo. These were the kinds of deep sky objects he had built this telescope to capture, and seeing them in his final processed images made all the effort worth it.

Back at home, he also took a shot at imaging the Orion Nebula, M42, from his balcony. With about three hours of exposure time using a light pollution filter, he pulled out incredible detail and color, proving that even in a less-than-perfect environment, this telescope was capable of capturing stunning astrophotography.

At the end of the project, the telescope was performing well, but there were still things to improve. The focuser needed minor tweaks to get the fit just right. Collimation was a bit finicky and could use a better adjustment system. But the biggest limitation was actually his mount. It wasn’t originally built for long-exposure astrophotography, so tracking at this level of magnification was pushing it to its limits. That would be the focus of his next project, modifying and refining the mount to improve its guiding performance.

For those interested in building their own version of this telescope, he made the project files available on his website and Printables. He also provided links to the parts he used, and for anyone wanting to support his work, he offered ways to contribute through his YouTube channel and Patreon.

In the end, this was more than just another 3D-printed telescope, it was proof that with enough creativity, persistence, and trial and error, you could build something from scratch that was actually capable of capturing stunning images of space.