For most of us who are not astronomers, the image that comes to mind when describing a reflecting telescope is of a huge instrument in its own domed-roof building on a mountain top. But a reflecting telescope doesn’t have to be large at all, as shown by the small-but-uncompromising design from [Lucas Sifoni].

Using an off-the-shelf mirror kit with a 76mm diameter and a 300mm focal length, he’s made a pair of 3D-printed frames that are joined by carbon fibre rods. The eyepiece and mirror assembly sit in the front 3D-printed frame, and the eyepiece is threaded so the telescope can be focused. There’s a 3D-printed azimuth-elevation mount, and once assembled, the whole thing is extremely compact.

While a common refracting telescope uses a lens and an eyepiece to magnify your view, a reflector uses a parabolic mirror to focus an image on a smaller diagonal mirror, and that mirror sends the image through the eyepiece. Most larger telescopes use this technique or a variation on it because large first-surface mirrors are easier to make than large lenses. There are also compound telescope types that use different combinations of mirrors and lenses. Which one is “best” depends on what you want to optimize, but reflectors are well known for being fairly simple to build and for having good light-gathering properties.

If you’d like to build your own version of this telescope then the files can all be found on Printables, meanwhile this isn’t the first 3D-printed telescope you might have seen on these pages. If you want to make your own mirror, that’s a classic hacker project, too.