Overhead Alerts
An on-device alert — with Live Activity and Dynamic Island support — when a chosen aircraft type is flying overhead. Delivered locally; no push servers involved.
iOS · Coming soonWatch the sky,
Watch the sky,
by the numbers.
Track real aircraft overhead, forecast contrail conditions from atmospheric data, and log the sky with a community of fellow sky watchers.
Coming soon to theApp Store
Scan to keep
this page · chemyapp.com
Sky Score72Moderate today
Sky Score
72/100
Moderate — Some persistent contrails are possible today.
Aircraft in range
14
Live public ADS-B within range
Geomagnetic
Kp 3
Kp index · NOAA SWPC
Features
Real instruments for reading the sky.
Four ways Chemy turns the sky into data you can actually work with — every reading sourced from real, public information.
Live overhead
Real-Time Tracker
A live map of the public aircraft above you, drawn from real ADS-B data. Tap any plane for its type, operator, altitude, callsign, and route — and filter by altitude band or aircraft type.
Today's sky
Contrail Forecast & Sky Score
A transparent 0–100 Sky Score for how contrail-favorable the sky is today, computed from Open-Meteo upper-air data with the Schmidt–Appleman criterion. Every factor is shown — no black boxes.
On-device
Contrail Score Camera
Point your camera at the sky and Chemy scores the contrail coverage and persistence in your shot, with time-lapse capture. The analysis runs entirely on your device — your frames are never uploaded.
Moderated
Community Sky Sightings
Log and share geotagged observations on a global map and a realtime feed, follow other watchers, and see what's nearby — with day-one moderation: keyword filtering, reporting, blocking, and fast takedown.
And more
Built out, end to end.
AR Directional Mode
Point your phone at the sky for augmented-reality guidance toward tracked aircraft positions.
Private Sky Journal
A private, on-device journal of your observations that stays available offline — it never leaves your phone.
Cloudbuster Build Hub
Browse cloudbuster and orgonite build guides and galleries of other makers' builds — shared as hobbyist art and decor, with no efficacy claims.
Field & Frequency Lab
For entertainment only: visualize your phone's magnetometer, play tones, and view live NOAA space-weather data.
Widgets & Siri
Home and lock-screen widgets, “what's overhead?” via Siri and App Intents, and shareable Sky Score cards.
Private by design
Your sky stays yours.
Chemy collects as little as possible and processes most of it on your phone.
No tracking, ever
No ads, no advertising identifier, no third-party analytics or telemetry SDKs. Chemy does not follow you across apps.
On-device by default
Contrail scoring and your Sky Journal stay on your phone. Only the community posts you publish are stored on our servers.
Private accounts
Chemy uses Sign in with Apple — one tap, with Hide My Email supported. You can delete your account and its data anytime.
Coming soon
Be first in line.
Chemy launches on the App Store soon. Until then, read exactly how it works and how your data is handled — no surprises.