About Transit Chaser

Transit Chaser is a free web app built to help photographers catch those rare moments when aircraft line up with the Sun, Moon, contrails, or even other aircraft from your point of view.

It started as a personal project, mostly because I wanted a better way to chase aircraft transits without guessing, refreshing flight trackers all day, or relying only on luck. Over time, it slowly turned into something bigger, with people from different parts of the world testing it, sending feedback, and helping shape what it is today.

My Story

I’m Rey, an astrophotographer based in Sydney, Australia. I first got pulled into astrophotography because of the Moon, deep sky objects, and the strange feeling of trying to capture things that are always moving, always changing, and never quite waiting for you.

Around 2021, I became obsessed with aircraft transits. There was something about seeing a plane cross the Moon or Sun for a fraction of a second that felt impossible and addictive at the same time. The problem was that planning those shots was messy. I was using flight trackers, checking paths manually, watching the sky, writing down times, and hoping everything lined up.

After doing that again and again, I started noticing patterns. I began collecting notes, testing angles, checking where aircraft appeared compared to the Moon and Sun, and slowly working out the geometry behind it. That rough manual process eventually became the foundation for Transit Chaser.

Why I Built It

Transit photography is beautiful, but it can also be frustrating. A great shot can come and go in less than a second. If you are looking in the wrong direction, using the wrong location, or relying on delayed information, the moment is gone.

The goal of Transit Chaser is simple: make it easier for photographers to know when something interesting might happen in the sky. It combines live aircraft data, Sun and Moon positions, your location, and a bit of geometry to estimate possible alignments.

It is not perfect, and it never will be. Aircraft turn, climb, descend, disappear from data feeds, or change speed without warning. But the app is designed to give photographers a better chance than guessing.

What The App Can Do

Transit Chaser can help with several types of sky photography:

• Aircraft crossing or passing near the Moon
• Aircraft crossing or passing near the Sun
• High altitude aircraft and contrail opportunities
• Plane on plane alignments from your viewing location
• Plane watch alerts for aircraft that match selected filters
• Big plane schedule checks for selected aircraft around Sydney

The app also includes adjustable detection margins, prediction windows, local saved settings, email alerts, and different data-source fallbacks to make it more useful in real-world conditions.

A Community Project

Transit Chaser is still a small, independent project. It is not backed by a company, and it is not a commercial flight-tracking platform. It is something I built because I love this kind of photography and wanted to share it with others.

A lot of the app has improved because people tested it in different countries, under different skies, with different aircraft data coverage. Every report helps. Every bug report helps. Every screenshot, suggestion, and weird edge case makes the app better.

If you use Transit Chaser and manage to capture something cool, I would genuinely love to see it.

A Note About Flight Data

Transit Chaser uses third-party and community flight-data sources to estimate aircraft positions. I do not own or control those data sources. The app simply uses available data to help photographers plan possible shots.

Flight data can be delayed, incomplete, wrong, blocked, rate-limited, or unavailable. For that reason, Transit Chaser should only be used as a photography and hobby tool. It should never be used for aviation safety, navigation, drone operation, emergency decisions, or anything safety-critical.

How It Was Built

The app has been built through a mix of real-world testing, manual observations, trial and error, and a lot of late-night problem solving. Some parts of the code and documentation were created with help from OpenAI tools, then tested and adjusted around real use.

Because of that, mistakes can happen. If you notice something broken, inaccurate, confusing, or outdated, please let me know. I would rather fix it than pretend the app is perfect.

Special Thanks

A big thank you to Louis (@louis.dmng on Instagram) for helping with overseas reports, testing the app, and sending feedback while the project was still taking shape.

Thank you as well to everyone who has tested Transit Chaser, reported bugs, suggested features, shared screenshots, or simply used the app in the field. This project would not be improving without that help.