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| The 3D-printed DIY telescope (pictured in hands-on photos) uses carbon rods for structural support. |
November 18, 2025 — In a world where technology constantly shrinks, a new personal project from developer and hobbyist Lucas Sifoni takes portable astronomy to an almost unbelievable extreme. Documented in a detailed blog post, Sifoni has successfully designed, built, and tested a fully functional Dobsonian telescope so compact it’s designed to fit inside a jacket's inner pocket.
The project, aptly named the "Miniscope," redefines what it means to have a grab-and-go astronomical instrument, proving that powerful optics don't always require a bulky footprint.
Engineering for the Pocket
The primary constraint was clear from the start: ultimate portability. According to the project notes, every component was chosen or designed with this goal in mind. The optical heart of the telescope is a 76 mm parabolic mirror with a 300 mm focal length, creating a fast f/4 system that gathers a surprising amount of light for its size.
The entire structure is a marvel of modern DIY, being 3D-printed from PETG carbon-fiber filament. This material choice provides the necessary rigidity to maintain precise optical alignment while keeping the overall weight to an absolute minimum. The only parts not fitting in that coveted jacket pocket are the slim carbon fiber rods used for structural support—a trade-off for stability that seems more than reasonable.
For those interested in the complete build process, Sifoni has shared extensive documentation. You can find the full story, design philosophy, and technical deep dive on his blog: Inside the Miniscope: Building a Jacket-Pocket Telescope.
Classic Dobsonian, Modern Execution
The telescope’s mechanics pay homage to the classic, beloved Dobsonian design—prizing simplicity, smooth movement, and perfect balance. The altitude and azimuth motions (allowing you to swing the telescope up/down and left/right) use an improvised but effective bearing system: pads made from UHMW or HDPE (materials often used for furniture sliders) paired with rubber for tension.
Innovation shines in the details. The carbon rods are slightly forced into an arch, creating a locked, tensegrity-like structure. Mirror alignment, or collimation, is achieved with nylon screws, and the secondary mirror is held securely in place with magnets. Perhaps the cleverest touch is the focuser: a completely hardware-free, friction-based eyepiece holder that relies on the flexible grip of the 3D-printed plastic itself.
A lightweight Lycra shroud wraps the open truss structure, serving the dual purpose of blocking stray light and slowing down dew formation on the precious mirrors—a common nuisance for astronomers.
Putting the Optics to the Test
No serious telescope project is complete without rigorous optical testing, and Sifoni’s documentation is impressively thorough. Screenshots of interferograms and star tests tell a story of refinement. The initial, inexpensive mirror arrived significantly overcorrected, a common issue. Through careful refiguring, the performance was dramatically improved.
The final result? The builder reports clean star images and a calculated Strehl ratio of around 0.9. In simpler terms, this means the tiny mirror delivers about 90% of the theoretical maximum sharpness possible for a perfect mirror of its size. While the small aperture inherently limits the resolution for splitting close double stars or seeing fine planetary detail, the optical quality is exceptionally high for a custom, portable build.
A Niche Masterpiece
Sifoni is clear that the Miniscope isn’t meant to compete with larger commercial telescopes. Its achievement lies elsewhere. It stands as a successful proof-of-concept and a genuinely usable optical device at a rarely seen scale. It embodies the spirit of amateur astronomy: innovation, hands-on building, and the pure joy of creating a personal window to the cosmos.
For the maker community and aspiring astronomers, the project is a gift. All 3D files, comprehensive assembly notes, and raw optical test results are publicly available for anyone who wants to replicate or modify the design.
Inspired to start your own stargazing journey? For those looking for a more traditional, ready-made portable option, a popular choice is the Celestron Travel Scope 80 Portable Refractor Telescope, available on Amazon. Whether you build it yourself or unpack it from a box, the universe is waiting.
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| Pre-refiguring test pictures from the telescope. |