Collective sky
monitoring
ContrailsLog is a citizen science platform. Anyone can contribute by reporting sightings and help build a searchable public database.
How to contribute
The process is simple and takes less than two minutes. Every log enriches the database and improves analysis quality.
Observe and point your phone at the sky
When you notice anomalous trails, open ContrailsLog and point your phone at the sky. The gyroscope records the exact orientation in real time — like an AR app.
Trace the trails point by point
Press the centre button to plant a point where the crosshair points. Follow the trail by moving your phone and add as many points as you like — even beyond the screen edges.
Confirm and map
Press ✓ to confirm the trail. The system calculates the real length at 10 km altitude and projects it on the map with precise GPS coordinates.
The system monitors weather data
In the 24–72 hours following each report, the system automatically collects real weather data: precipitation, UV/UVB index, cloud cover.
Pattern analysis over time
With enough reports, the system searches for statistical correlations between sightings and subsequent weather changes. Results are publicly available and exportable as CSV.
What makes ContrailsLog different
How to identify
and document trails
A practical guide based on visual observation, atmospheric behaviour, and documentation criteria for quality reports.
Contrails vs Persistent Trails
Aerial trails are normally generated by the condensation of water vapour from engine exhaust at high altitudes. Behaviour varies significantly depending on atmospheric conditions. It is important to distinguish normal from anomalous behaviour to produce accurate reports.
| Characteristic | Normal (contrail) | Anomalous / Worth reporting |
|---|---|---|
| Duration | Disappears within seconds or minutes | Persistent beyond 30–60 minutes |
| Expansion | Remains thread-like and dissolves | Spreads progressively into artificial cirrus |
| Count | Occasional, consistent with air traffic | Multiple and clustered — 5–15 trails in a short time |
| Pattern | Trajectories consistent with flight routes | Crossed patterns, grids, tight parallels |
| Sky effect | No significant change | Sky turns milky white within hours |
| Weather conditions | Consistent with high humidity at altitude | Persistent trails even with low humidity or clear sky |
How to photograph correctly
A good photo increases the value of the report and makes it easier for other users to confirm.
Trail behaviour over time
What NOT to do
Citizen science
for a transparent sky
ContrailsLog was born from the idea that systematic, rigorous documentation is the most effective tool for observing and understanding what happens in the sky above us.
Why ContrailsLog exists
No structured platform currently exists that allows citizens to systematically document anomalous aerial trails and correlate these observations with verifiable weather data.
ContrailsLog aims to fill this gap: building a reliable, methodical archive of aerial trail data, accessible to journalists, researchers, and citizens.
The more users contribute, the denser the network and the more statistically meaningful the analysis. The Project è collettivo per definizione.
Roadmap
How the Pattern Detection system works
One of the most ambitious features is the automatic search for statistical correlations between user reports and real weather data collected in the hours and days that follow. The goal is to surface patterns objectively and transparently.
📌 Zone with 5+ reports in 7 days + UV variation >20% above average → anomalous UV pattern
📌 Zone with recurring reports + rain within 24h in 70%+ of cases → precipitation correlation
📌 Geographic cluster of reports concentrated in specific time windows → temporal pattern
The system requires a minimum number of reports per zone before showing any pattern, to avoid false positives on insufficient data.
Project principles
Public record of
pressures & threats
Every attempt to intimidate, silence, or interfere with this project is documented here publicly and permanently. Transparency is our protection.
This record documents any pressure, threat, legal warning, takedown request, surveillance, or interference received by this project. Making these incidents public is the most effective deterrent: intimidation loses its power when it is visible.
• Legal threats or cease-and-desist letters
• Requests to remove data, photos, or reports
• Government or agency inquiries
• Pressure on hosting providers or infrastructure
• Surveillance or monitoring of contributors
• Attempts to discredit the project or its contributors
• Account suspensions, domain seizures, or platform bans
• Any form of direct or indirect intimidation
Incident log
All documented incidents, in reverse chronological order.
Our response protocol
Tools & references
A curated list of tools, databases, and organisations useful for anyone monitoring and documenting aerial activity.