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Boosted Mode is the more advanced transit checker. It uses 3D geometry to compare the aircraft’s real position in the sky with the Sun or Moon, instead of relying only on a simple angle check.
It looks at the aircraft’s track, altitude, climb or descent, distance from you, data quality, and the apparent size of the Sun or Moon. This helps separate real transits, grazing passes, near misses, and loose sky candidates.
For serious transit hunting, the lower end gives you fine control from 0.1° to 4.0°. Smaller values are tighter, while larger values give you a broader heads-up area. These margins are warnings, not guarantees.
Test mode. Off uses the current SunCalc. On uses SunCalc 2 anywhere Transit Chaser calculates Sun/Moon positions.
Email alerts follow the selected Transit Mode. This page must stay open for alerts to send. To avoid spam, alerts are grouped into one email when multiple aircraft are detected at once. Your email address is saved only in this browser and is not stored by Transit Chaser. Please check your spam or junk folder, as alert emails may occasionally end up there.
Paste a real Flightradar24 API token from an active API subscription. Transit Chaser uses it only in this tab and sends it through the Vercel proxy for each request. The app does not save the token.
Use only a token you own or have permission to use. Flightradar24 credits will be charged to that token. This mode uses the same search-radius, detection-margin, prediction, and refresh controls as the normal tracker. Moderator safety limits are applied automatically.
Paste your temporary Cloudflare tunnel /data.json URL here to check your dump1090 receiver.
This is a test panel only; it does not replace your normal flight source or transit maths.
Transit Chaser is a free aircraft-transit photography project built by Sydney astrophotographer Rey Sandu Godakumbura. It grew out of years of manually watching flight paths, comparing aircraft positions with the Sun and Moon, testing angles in the field and trying to improve the chances of being ready for a transit that may last less than a second.
The app combines the observer's location with live community-supplied aircraft position data and the calculated position of the Sun or Moon. It compares those moving aircraft with the target in the sky and can warn about possible alignments. The app also includes a Location Planner, contrail and plane-on-plane modes, Plane Watch filters, adjustable detection margins and other tools for photographers who want to explore local aircraft traffic.
Transit Chaser does not claim that every alert will become a photograph. Aircraft can turn, climb, descend or disappear from a data feed, and different ADS-B networks can update at different times. The project is therefore tested against real observations and user reports, with the aim of improving a photographer's chances rather than presenting a safety-critical aviation service.
The Community Gallery contains original transit photographs submitted by photographers and manually reviewed before publication. The guides explain aircraft-transit photography, Sun and Moon shooting, solar safety, detection margins and the basic geometry used by the app. These pages document the project for people who want more than the live tracker itself.
How Transit Chaser works How to use the app Detection margin guide Photography guides Community Gallery About the project
Transit Chaser has become expensive to keep online. If the app has helped you, a quick follow on Instagram genuinely helps spread the word and keep the project growing.
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