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A TELESCOPE YOU CAN TAKE HIKING

A real telescope designed to come with you on runs and hikes, not one that lives in a dome.

by Lucas Sifoni

FULL CAD BOM FIRMWARE DOCS

Science

Built with3D printing

difficulty
●●●●●
time
weeks or months
license
CC-BY-NC-SA
repo
repo 0 stars

WHAT YOU’LL NEED

1
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COMPAREE VERDICT

Wallace is Lucas Sifoni's 153mm f/2.8 ultra-wide-field Newtonian, built to frame whole objects like the North America Nebula (NGC 7000) and small enough to carry in a backpack on a hike. The structure is open: two 3D-printed modules on a Vixen-style dovetail, stiffened by six solid carbon rods, printed in ASA, with a simple 6-point mirror cell on three levers and a 4-element GSO coma corrector designed by Roger Ceragioli. The STL files and a full parts list are free on Printables under CC BY-NC-SA. What you cannot download is the mirror. Lucas ground and figured the 430mm focal length primary himself, needed two attempts, and ended at a Strehl of 0.92 in the instrument. If you already make mirrors or can source a fast 150mm primary, this is a well-documented, proven design. If you cannot, the printed parts alone will not get you there, and his separate 150mm f/5 printable kit is the more realistic route.

GOOD TO KNOW

  • —17 STL files and a PDF are published on Printables and mirrored on lucassifoni.info.
  • —A full parts list is included: primary mirror, GSO corrector, 360mm dovetail, secondary, six carbon rods, bearings, screws and springs.
  • —Licence: Creative Commons BY-NC-SA (Printables). Editable source CAD files were not found.
  • —There is no step-by-step assembly guide; the blog post and the Cloudy Nights and Astrosurf threads cover the mirror making and design choices.
  • —No electronics or firmware are involved.
  • —Weight is not stated by the creator.

Parts to buy

8 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • 155mm f/2.8 primary mirror (430mm focal length)Find
  • 54mm secondaryFind
  • GSO 4-element coma correctorFind
  • 360mm Vixen-style dovetailFind
  • Six carbon rodsFind
  • 623ZZ bearingsFind
  • ScrewsFind
  • SpringsFind

Can I build this?

Print17 parts in ASA: cages, focuser, mirror cell, secondary and corrector hubs
Buy155mm f/2.8 primary mirror (430mm focal length), 54mm secondary, GSO 4-element coma corrector, 360mm Vixen-style dovetail, six carbon rods, 623ZZ bearings, screws, springs
Tools3D printer, basic hand tools; mirror grinding and testing equipment if you make your own primary
SkillsAdvanced: mirror making or sourcing, optical alignment, corrector spacing
TimeWeeks to months if you make the mirror yourself; the printed parts are much quicker
CostMostly the mirror. The corrector cost Lucas 65 euros used; a finished Wallace from him is 2,215 euros
SafetyNever point the telescope at the Sun without a certified full-aperture solar filter; a fast mirror concentrates sunlight and can blind you instantly or start a fire. Use normal care with glass grit and polishing compounds if you grind a mirror.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read Lucas Sifoni's write-up (Covers the mirror, the corrector spacing, the cell and the dovetail design, plus photos from a hike.)
  2. 2.Get the files and parts list (Download the STL files and check the parts list. Printed in ASA on a Bambu P1S.)
  3. 3.Plan the primary mirror (The primary mirror is the hardest part. This thread documents how he ground and figured it.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • The primary mirror is the gate: 155mm physical diameter, 430mm focal length. It is not a common off-the-shelf part, and Lucas made his own.
  • At f/2.8 a coma corrector is mandatory. The GSO 4-element corrector ships with about 56mm backfocus, but Wallace worked best with it re-spaced to around 79mm.
  • Collimation tolerances at this focal ratio are tight, so the mirror cell and secondary adjustments matter.
  • Lucas notes the solid mirror needs about 30 minutes to cool to ambient before the image settles.
  • Edge correction starts to fall off beyond roughly two thirds of the field.
  • The parts list gives the secondary as 54mm while the blog post mentions a 59mm secondary, so check the blog and forum threads before buying optics.
  • The licence is non-commercial: you can build one for yourself, but not sell copies.

Can I download plans or STL files for Wallace?

Yes. Lucas Sifoni published the printable parts (17 STL files plus a PDF) on Printables and mirrored them on his website, with a full parts list. The licence is Creative Commons BY-NC-SA, so personal builds and remixes are fine but commercial use is not.

What does f/2.8 mean, and why does it matter?

The focal ratio is focal length divided by aperture. Wallace's primary has a 430mm focal length on a 153mm clear aperture, about f/2.8. That gives a very wide, bright field, but coma is severe, so a coma corrector is mandatory and collimation tolerances are tight.

Where do I get a 153mm f/2.8 mirror?

This is the real gate. Lucas ground and figured his own primary on a sine table, and it took two attempts. A mirror this fast is not a common catalogue item. If you cannot get one, he points to his separate printable 150mm f/5 kit, which uses commonly available parts.

What does it cost?

Lucas bought the 4-element GSO coma corrector used for 65 euros; the mirror is the expensive and difficult part unless you make it yourself. He also builds finished Wallace telescopes one at a time through Chantepierre Optique, listed at 2,215 euros including tax.

Is this harder than a normal Dobsonian telescope build?

The printed structure is not the hard part. The fast primary mirror and the correct spacing of the coma corrector (he found the best backfocus around 79mm, not the 56mm the corrector ships with) are what make it demanding.

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Discussion1

FROM THE COMPAREE TEAM

Wallace frames the whole North America Nebula in one view and fits in a backpack. Would you grind a mirror this fast yourself, or start with a slower, easier primary?

CompareeTEAM1d ago

Practical notes from our verification: the files are real and free on Printables (CC BY-NC-SA), with a complete parts list, and Lucas's own blog post explains the design. The optical figures come from him: a 153mm primary at f/2.84, 430mm focal length, a Strehl of 0.92 in the instrument, and more than 4 degrees of true field with a 100 degree eyepiece. The catch is the mirror, which he made himself. He also sells finished Wallaces built one at a time.

Lucas Sifoni

Lucas Sifoni is a software developer and amateur mirror maker based in Cahors, France. He built Wallace in 2025 as an ultra-wide-field deep-sky telescope, grinding and figuring the primary mirror himself, and now carries it in a backpack on hikes to observe from cliffs and open ground.

GitHub Web

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  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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