Hadley is a 3D-printed-structure Newtonian reflector with a 114 mm aperture and 900 mm focal length. It is a build project, not a complete telescope kit: you still need a compatible mirror set, eyepieces, hardware, structural rods, a mount, printing, assembly, and optical alignment. The design’s modular printed parts make it unusual, but the real cost and effort depend on sourcing and fitting those components.
What the Hadley telescope is—and what it is not
Hadley was created by Jonathan “Maff” Kissner as a Newtonian reflector with a spherical primary mirror and elliptical secondary. The assembly guide specifies a 114 mm aperture, 900 mm focal length, and a 25 mm elliptical secondary mirror. Its structural parts are 3D printed; the optical surfaces and the rest of the working setup are not included in the files. See the creator’s project page and assembly guide for the design details.
The creator describes the telescope as an attractive alternative to entry-level scopes and as capable for planetary observing. Those are the maker’s characterizations, not independently established optical test results. The available documentation does not provide controlled testing to substantiate a quantified performance claim.
What parts do you need to build Hadley?
The project files do not turn a printer into a complete telescope. Plan for these separate items:
Free tools Windows power users keep installed
One-click scans. No signup required.
#1 Best Overall
- SMARTPHONE-POWERED SKY TOUR: No experience needed! Just dock your phone, launch the StarSense Explorer app, and follow the on-screen arrows to locate stars, planets, nebulae, and more.
- PATENTED STARSENSE TECHNOLOGY: Unlike other astronomy apps, StarSense Explorer uses sky recognition technology to turn your phone into a celestial navigation system, analyzing star patterns overhead to pinpoint your telescope’s position.
- TONIGHT’S BEST TARGETS, INSTANTLY: The app generates a curated list of the top objects to see based on your time and location. See planets, bright nebulae, galaxies, and star clusters from the city—and even more from dark skies.
- SIMPLE SETUP, SMOOTH TRACKING: Features a manual altazimuth mount with altitude slow motion adjustment with a sliding rod. Follow the on-screen arrows to your target; when the bullseye turns green, you can view it clearly through the eyepiece.
- 114MM REFLECTOR WITH IMPRESSIVE VIEWS: The 4.5" Newtonian reflector with high-reflectivity coatings delivers sharp, vivid views of the Moon, planets like Jupiter and Saturn, and deep-sky favorites like the Orion Nebula and Andromeda Galaxy.
- Printed structure: the Hadley parts, printed to match the chosen design version.
- Optics: a compatible 114 mm / 900 mm spherical primary and a 25 mm elliptical secondary. Confirm the dimensions and optical type against the version you are building; a listing mentioned by the creator is not proof of current availability or universal compatibility.
- Hardware and supports: structural rods, fasteners, and springs for the primary mirror cell. The original guide specifies three rods about 36 inches long and #10-24 fasteners.
- Mirror adhesive: soft-curing silicone-based adhesive. The manual warns that superglue or epoxy can deform a mirror enough to degrade the image.
- Eyepieces: 1.25-inch format. The guide suggests a low-power and a higher-power option.
- Mount: a sufficiently stiff support for aiming and observing; it is a separate part of the project.
- Tools and time: a suitable FDM printer, assembly tools, and time for fitting and optical alignment.
The metric remix uses M4 hardware rather than the original’s #10-24 fasteners. Its bill of materials and files are a separate build route; do not mix dimensions or hardware from the imperial original and metric remix without checking fit. The official metric remix page lists its own parts and test-print guidance.
Will the parts fit on your 3D printer?
The creator’s 2022 PDF reports a published print profile of 10 pieces, 832 g of PLA, and 32.53 hours, using a Prusa MK3/S/S+ example. Those are metadata for that profile, not a guarantee of the print time, material use, or fit on another printer. The documentation available here does not establish a universal maximum part dimension, so check the current files in a slicer against your printer’s usable build volume before committing to the full set.
Rank #2
- LARGE APERTURE: This Newtonian telescope has a 114mm aperture for exploring the Moon, planets and deep sky objects.
- MULTIPLE MAGNIFICATIONS: The reflector has a 500mm focal length and comes with 2 eyepieces for powers of 19x and 51.5x.
- EXPLORE SIMPLE ASTROPHOTOGRAPHY: A special adapter helps you image the Moon or other targets using a smartphone.
- FULL ACCESSORY PACKAGE: This telescope comes with an alt-azimuth mount, a full-size tripod and a red dot viewfinder.
- A LEADER IN EXPLORATION: The National Geographic name means quality construction and thorough support from our team.
Dimensional accuracy matters because printed sockets and pockets have to fit purchased rods, screws, nuts, and optics. The assembly guide advises against scaling beyond 1–2% because scaling can interfere with purchased-part fit. It recommends printing a test piece first to check rod fit, screw holes, and nut pockets; the metric remix likewise provides a hardware test print and advises adjusting CAD tolerances if needed.
Printing settings and material considerations
The assembly guide reports good results with PLA and says PETG and ABS have also been used, while noting their temperature-control and dimensional-accuracy challenges. Its suggested starting settings are 30% cubic infill and four perimeters with a 0.4 mm nozzle, or three perimeters with a 0.6 mm nozzle. These are recommendations for the documented design, not universal settings for every printer or filament.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Rank #3
- PERFECT ENTRY-LEVEL TELESCOPE: The Celestron PowerSeeker 114EQ is an easy-to-use and powerful telescope. This 114mm Newtonian Reflector offers enough light gathering ability to see planets, the Moon's craters, distant stars, the Orion Nebula, and more.
- MANUAL GERMAN EQUATORIAL MOUNT: With its slow-motion altitude rod, the German Equatorial mount allows you to navigate the sky with ease. Find celestial objects quickly and follow them smoothly & accurately as they appear to drift across the night sky.
- COMPACT AND PORTABLE: The ideal telescope for adults and kids to use together, the PowerSeeker is compact, lightweight, and portable. Take it to your favorite campsite, a dark sky observing site, or simply the backyard.
- MULTIPLE ACCESSORIES: The Celestron PowerSeeker 114EQ Telescope comes with 2 quality eyepieces (20mm and 4mm) plus a 3x Barlow lens to triple the power of each. You'll also receive a FREE download of one of the top-rated astronomy software programs.
- UNBEATABLE WARRANTY & SUPPORT: Buy with confidence from Celestron, a leading telescope brand in California since 1960. Your purchase includes a 2-Year US Warranty and unlimited support from our team of US-based experts.
The guide emphasizes that stronger prints generally come from adding perimeters rather than simply increasing infill. As it puts it, “The way to stronger prints is ‘more perimeters’ rather than higher infill.” Follow the current files and guide for the version you choose, then validate critical fits with a test print.
Choosing eyepieces for low and high power
Hadley accepts 1.25-inch eyepieces. The focal-length trade-off is straightforward: a shorter eyepiece focal length gives greater magnification but a narrower view of the sky. The assembly guide’s examples are a 25 mm Plössl or 23 mm aspheric for low power, and a 6 mm or 9 mm wide-angle or planetary eyepiece for higher power. These are examples, not a guarantee that every eyepiece design will perform identically.
Rank #4
- SMARTPHONE-POWERED SKY TOUR: No experience needed! Just dock your phone, launch the StarSense Explorer app, and follow the on-screen arrows to locate stars, planets, nebulae, and more.
- PATENTED STARSENSE TECHNOLOGY: Unlike other astronomy apps, StarSense Explorer uses sky recognition technology to turn your phone into a celestial navigation system, analyzing star patterns overhead to pinpoint your telescope’s position.
- TONIGHT’S BEST TARGETS, INSTANTLY: The app generates a curated list of the top objects to see based on your time and location. See planets, bright nebulae, galaxies, and star clusters from the city—and even more from dark skies.
- SIMPLE SETUP, SMOOTH TRACKING: Features a manual altazimuth tabletop Dobsonian-style base. Follow the on-screen arrows to your target; when the bullseye turns green, you can view it clearly through the eyepiece.
- 114MM REFLECTOR WITH IMPRESSIVE VIEWS: The 4.5" Newtonian reflector with high-reflectivity coatings delivers sharp, vivid views of the Moon, planets like Jupiter and Saturn, and deep-sky favorites like the Orion Nebula and Andromeda Galaxy.
The metric remix notes 6 mm and 25 mm Svbony eyepieces as examples, and lists finder and collimation accessories as possible additions. They are examples in that remix author’s build notes, not verified current product listings or required parts.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Choose a mount for stiffness, not just appearance
The metric remix author cautions that the original square rocker frame is not stiff enough for enjoyable use. Suggested alternatives include a wooden frame, aluminum extrusions with a printed bearing mount, or an improved printed mount design. In comparing options, consider vibration and stiffness alongside construction effort, material access, and portability. The printed telescope structure alone is not a complete observing setup.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsBest Value
- Caliber: 114mm, Focal length: 900mm
- Surface accuracy： 1/10 λ
- Enhanced aluminum and protective coating
- Reflectance at: 92% / 400-950nm
- Major axis of secondary mirror: 35mm , minor axis: 25mm
How much does a Hadley build cost?
There is no verified current total in the project documentation. At the time of the creator’s project-page posting, Kissner estimated “around $100 in material” plus eyepieces, suggesting a good pair might total $50; the page also warns that component prices fluctuate. In a 2022 PDF, he summarized the total project cost as “< $150.” These are historical, creator-reported estimates, not current quotes or independently audited totals. They do not establish today’s cost for optics, filament, hardware, rods, mount, or accessories.
Before buying anything, choose either the imperial original or metric remix, compare its bill of materials with the exact mirror set and hardware listings you can obtain, and price the mount and eyepieces as separate costs. The creator’s page reported an Amazon mirror listing at the time of its update; that does not confirm present stock, price, or compatibility with every remix.
Is Hadley a sensible project for you?
- Consider it if you want to learn how a Newtonian is assembled, can print accurately, and are prepared to source and align the optics and build or obtain a stable mount.
- Plan extra care if you need to mix suppliers or hardware versions: dimensional mismatch can waste print material and assembly time.
- Look elsewhere if you want a ready-to-use telescope with optics, accessories, and mount included, or if you cannot verify that the printer and purchased components fit the selected files.
Kissner’s creator PDF says, “Building a telescope is the best way to learn how one works.” That captures Hadley’s clearest appeal: a hands-on telescope project with a printed structure, rather than a low-cost shortcut to a turnkey instrument.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
