Open instrument for anomalous aerial phenomena · v0.1.0
Unexplained should not mean unmeasured.
Thousands of people report something in the sky every year. Almost none of it produces a record worth arguing about: one shaky camera, no clock, no second angle, no way to rule out a satellite. The mystery is real. The evidence is terrible.
nband is a fix for the evidence. A sensor node watching up to thirteen bands at once, timestamped to GPS within a few hundred nanoseconds, publishing everything it records to an open archive. The entry build costs about what a used laptop does and watches six of those bands; thirteen is the full build. Most of what any of them catches will be aircraft. That is the point: you cannot say a thing is unexplained until you have properly ruled out the explanations.
Behind this text: one node, its detection shells at their real ranges, and something crossing them. A band lights as the object enters its range. Two lit at the same instant is a coincidence, and a coincidence is the difference between a story and a measurement.
The instrument, by wavelength
Why every sighting falls apart
A camera alone can never settle anything
Every famous piece of UAP footage has the same flaw. A bright shape on one sensor, filmed at unknown range, with no independent measurement of anything. Nothing in the recording distinguishes enormous and distant from small and close, or says whether the thing was hot, whether it was transmitting, or whether it made a sound. The argument never ends, and it never ends because the recording never contained the answer in the first place.
The way out is asking every other band what it saw at the same instant. Something with an engine is hot in the thermal band and audible seconds later. A satellite is exactly where the orbital catalogue says it will be. A transmitting drone shows up on the radio. An insect near the lens shows up nowhere else at all. You do not need to guess when four independent physical channels disagree with each other.
Everything shares one clock, to the nanosecond
Every node disciplines its clock against GNSS satellites with a hardware pulse-per-second signal, holding a few hundred nanoseconds. That is what makes "at the same instant" a measurement instead of a figure of speech, and it is why two nodes 60 km apart can triangulate a real altitude rather than guess at one.
Nothing is kept until two bands agree
A single channel crossing a threshold is noise until something else agrees with it. When two bands trigger inside 250 milliseconds of each other, the node promotes the whole buffered window to permanent storage, including the 15 seconds that happened before the trigger fired.
Everything ordinary is subtracted first
Before anything is called interesting it is checked against aircraft transponders, satellite orbits, lightning networks, the site’s own radio interference, weather, and space weather. The overwhelming majority of events close as explained. A system that frequently finds mysteries has a calibration problem, not a discovery.
What it sees
Eleven ways of being wrong about the same object
Ionizing photons above 100 keV.
Radioisotope decay, cosmic-ray secondaries, and any source emitting hard photons. The only band in the stack that responds to nuclear rather than thermal or electronic processes.
Ultraviolet100 to 400 nanometres, above the violet edge of vision.
Corona discharge, electrical arcing, plasma, combustion, and lightning leaders. Solar UV sets the daytime floor, so the band is far more informative after dark.
Visible380 to 750 nanometres, the band your eye already covers.
Anything that reflects sunlight or emits its own light: aircraft, satellites, meteors, balloons, birds, and the occasional thing that fits none of those. Provides the astrometry that turns a detection into a bearing.
Near infrared750 to 1400 nanometres, just past the red edge.
Hot exhaust, incandescent surfaces, IR illuminators and rangefinders, and haze-penetrating reflected light. Silicon sensors are natively sensitive here, so removing the IR-cut filter from a normal camera buys the band for free.
Short-wave infrared1.4 to 3 micrometres. Reflective, not thermal.
Sees through haze, thin smoke, and some fog far better than visible light. Discriminates materials by reflectance in a way no other band in this stack can. Night-sky airglow illuminates targets passively at 1.5 to 1.7 micrometres.
Long-wave infrared8 to 14 micrometres. Pure thermal emission.
Everything warmer than absolute zero, by its own emitted heat rather than reflected light. Works in total darkness and through smoke. A radiometric sensor reports actual temperature per pixel, which turns a track into an energy-budget measurement.
Millimetre wave24 to 81 gigahertz active radar.
The only band in the stack that measures range and radial velocity directly, by illuminating the target and timing the return. Gives the discriminator a physical distance, which is what converts an angular track into a real trajectory.
Radio frequency500 kilohertz to 6 gigahertz, received passively.
Emissions rather than reflections. Aircraft transponders, satellite downlinks, control links, broadband impulsive noise from discharge events, and anything transmitting where nothing should be. Also feeds passive radar: an aircraft crossing a broadcast transmitter's illumination produces a Doppler-shifted echo.
Magnetic and ELF/VLFDC to 30 kilohertz field measurement, not photon detection.
Static and slowly varying magnetic fields, sferics from distant lightning, power-line harmonics, and any moving ferromagnetic or current-carrying mass close enough to perturb the local field. This is the band that has historically carried the most repeatable anomalous reports.
Acoustic and infrasound0.05 hertz to 20 kilohertz pressure waves.
Propeller and rotor signatures, jet noise, sonic booms, and the infrasound tail that survives to long range when audible sound has already been absorbed. Independently corroborates or refutes a claim that an optical track was silent.
SeismicGround motion from 0.008 to 100 hertz.
Ground-coupled acoustic energy from low overflights, and, at high-tier sites, the vibration reference a gravimeter needs to separate real gravitational signal from the ground moving underneath it.
The honest part
The top of the ladder is “unresolved”, and it stops there
The signal originated in the instrument: sensor glitch, hot pixel, shutter event, self-interference from the node's own emitters, condensation on optics, or a cable fault.
Matched to a specific catalogued object. An ADS-B airframe by hex code, a satellite by NORAD ID, a lightning stroke by network fix, a licensed transmitter by frequency and bearing.
Consistent with a known class but not matched to a specific object. A bird, an insect near the lens, a balloon, a meteor, an aircraft not transmitting ADS-B. Common and uninteresting, and by far the largest bucket after known sources.
Insufficient data to classify. Too few bands, too short a track, clock quality too poor, or the only witness channel was one the discriminator does not score alone. Not a mystery, just a bad measurement.
Survived every catalogue subtraction available, was witnessed coherently in two or more bands, and has kinematics or energetics the discriminator could not reconcile with any conventional class it knows. This is a statement about the limits of the catalogues, not a claim about the object.
An event cannot reach the top rung on one channel, or with a degraded clock, or when a catalogue the discriminator wanted to check was unavailable. Every lookup it performed is recorded, including the ones that found nothing and the ones it could not run. “We checked ADS-B and found no aircraft” and “we could not reach ADS-B” are different claims, and the archive keeps them different.
Build tiers
Start at the bottom. The grid treats every tier the same.
Tier 1 - Baseline
$504Visible, near-infrared, long-wave infrared, radio, environmental, and disciplined time. The minimum configuration that can contribute usefully to the grid.
Bill of materials →Tier 2 - Core
$1662Adds ultraviolet, millimetre-wave radar, acoustic, and magnetometry, and upgrades the thermal array to a 160x120 imager. This is the first tier that survives outdoors, and the weatherproof case and solar supply are most of the price increase rather than the sensors. The configuration the build guide is written against.
Bill of materials →Tier 3 - Extended
$5341Adds short-wave infrared, gamma spectroscopy, and a seismometer, and replaces the presence radar with an imaging one. The short-wave imager is close to half the tier on its own. Research-grade coverage without research-grade cost.
Bill of materials →Costs are the sum of sourced part prices as of July 2026 and exclude tools, shipping, and tax. Silicon pricing is unstable this year: Raspberry Pi boards have risen three times since December 2025 as memory supply moved to AI datacentre demand. The entry tier is held near its target by specifying a 2 GB board and writing firmware disciplined enough to run on it, not by pretending prices did not move.
Before you build one
Four things you should hear now rather than later
It will not prove anything on its own
A single node produces angular tracks with no range. Without range you have no size and no speed, only a direction and a brightness. The honest output of one node is a well-characterised question. Range comes from radar or from a second node, and the second node is usually the better buy.
Most of what it records is boring
Aircraft, satellites, birds, insects near the lens, and the neighbour’s motion light. Expect the overwhelming majority of events to close as explained. A system that frequently finds mysteries is a system with a calibration problem.
It demands a real site, not a windowsill
Glass blocks ultraviolet and is opaque in the thermal band. A node indoors is a node with four dead channels. It needs sky, power, a horizon survey, and somewhere the magnetometer is not sitting next to a refrigerator.
You will probably find nothing, and that counts
Five hundred hours of coverage turning up nothing unexplained is a real result. It puts a number on how often anything unusual crosses that patch of sky, which is something nobody can currently state. The archive is built to make that number computable rather than to make headlines.
It starts with one camera and a clock.
Ten steps, each ending in something you can check before spending money on the next: a command that prints an expected value, an image you can look at, a timing offset you can read. If a step does not verify, the guide names what usually causes it. You can stop after step five and still be contributing real data to the grid.