Terra Minima

A pocket field microscope that maps any surface the way orbiters map planets.

  1. (1)Introduction
  2. (2)How it sees
  3. (3)The atlas
  4. (4)Availability

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The launch film · 0:20

Thirty-four surfaces. One horizon.

0:00 / 0:20

Moss, moth wing, pollen, lichen, a survey map, a beetle, an eggshell, torn cotton paper, a fingerprint, coral, and twenty-four more. Each one framed as its own world, each one on the same curve.

(1) Introduction

Today Halden Optical is introducing Terra Minima, a pocket field microscope that maps any surface the way orbiters map planets: a leaf, a coin, a moth’s wing, at up to 400×, in full depth, stitched into one shared atlas of small worlds.

We have mapped the Moon to the metre and Mars to the centimetre. The surface of the leaf on your windowsill is, for almost everyone, uncharted. A conventional microscope shows you a flat disc of light. Terra Minima shows you terrain: ridges with heights, valleys with depths, and a horizon you can orbit.

It is the size of a lipstick and weighs 38 grams. Press it to a surface, hold still for under a second, and it returns a height map accurate to half a micron, with true colour, the lighting it was found in, and a place on the map.

Terra Minima: a small graphite cylinder with a knurled brass focus ring and a coated glass objective, on torn cotton paper beside a pressed fern
Terra Minima, shown near actual size. Graphite body, knurled brass focus ring, twelve-element objective.

(2) How it sees

Depth from focus, shape from light

Inside the body is a twelve-element apochromatic objective and a ring of eight narrow-band LEDs. For every scan, Terra Minima fires the ring in sequence while it sweeps focus through sixty-four planes. The focus stack gives it depth. The eight lighting angles give it the direction each facet faces. It fuses the two into a single terrain model, sharp from the highest spine to the deepest pore.

You can look at a scan flat, like a micrograph, or in Horizon mode, which wraps the terrain onto a globe and lets you fly along its edge. Every shot in the launch film is framed that way, on the same curve, so one surface hands over to the next.

Specifications
Magnification20× – 400×
Field of view12 mm – 0.6 mm
Depth resolution0.5 µm
Scan time0.8 s, 64 focal planes
Illumination8 narrow-band LEDs, 405–850 nm
Weight38 g
Battery600 scans per charge, USB-C

(3) The atlas

One map of the very small

Every scan can be pinned to where it was made. During a year-long field trial, 212 volunteers contributed 41,380 surfaces. They included botanists, paper conservators, a class of nine-year-olds in Oulu and a coin dealer in Lisbon. Browse by place, material or scale. You can walk from lichen on a Cairngorm boulder to frost on a Helsinki window without leaving a square millimetre.

Moss with sporophyte stalks along a curved horizon
Moss, Hampstead Heath · 60×
Glassy diatom shells glowing gold and cyan on black
Diatoms, lake sediment · 400×
Fern-like frost crystals under a deep blue sky
Frost on glass, Helsinki · 40×
Cubic sea salt crystals against cobalt blue
Sea salt, Guérande · 80×
Marbled paper swirling indigo, cream and gold
Marbled endpaper, 1891 · 30×
Stained plant stem cross-section, magenta and teal cells
Stem section, stained · 200×

The atlas is open. Scans are published under CC BY 4.0 by default, and the raw focus stacks can be downloaded for research.

(4) Availability

Shipping in November

Terra Minima ships in November 2026 for $249, including a year of atlas storage. It works with any recent iPhone or Android phone, or on its own, saving up to 2,000 scans until you are back in range.

For schools and museums there is the Field Kit: thirty instruments, a charging case and a lesson plan for every age from seven up. Applications for the first 500 kits open today.

Colophon. Terra Minima and Halden Optical are fictional, invented for this launch. The film, its sound, this page and its paper were made in code; the imagery was generated.