Tracking 19 amateur satellites (FM, linear and digital) with orbital elements from Celestrak updated 20 hours ago; passes are computed for your locator in the browser. Server snapshot, refreshed every 5 minutes. The tool below is live.
Updated
Your station:
| Satellite | Rises AOS | Max el | Length | Rises → sets | Downlink · uplink | Calendar |
|---|---|---|---|---|---|---|
| Loading orbital data… | ||||||
What it does
Shows every pass of 19 working amateur satellites over your station for the next 7 days: rise and set times, maximum elevation, sky track, and Doppler-corrected uplink and downlink for FM, linear and digital birds.
Data and refresh
Orbital elements come from the CelesTrak amateur group, refreshed every 24 hours and cached on this server. Frequencies come from the AMSAT status pages. Your locator never leaves the browser: SGP4 runs on your device.
How to read it
Pick a satellite card to see all its passes grouped by day. A pass above 30° is easy, above 45° is a gift. Open a pass for the polar plot: north at the top, the satellite rises at AOS and sets at LOS.
Who it is for
Anyone with a handheld and a small yagi can work SO-50 or the ISS repeater. Linear birds such as RS-44 need an all-mode radio. Start on a high FM pass, listen first, then call.
What it cannot tell you
The predictions are only as good as the elements behind them, and elements age: a day or two old is fine, a week old and the times start to slide by a minute or more. It cannot tell you whether the satellite is actually working either, because transponders get switched off, put into eclipse mode, or fail without the orbit changing at all. And it does not know your horizon. A pass that reaches 40 degrees is excellent on paper and useless if the direction it rises from is a block of flats.
Using it in practice
Sort the day by Max el and ignore anything under about 20 degrees until you have worked a few. Open the pass you want and look at the Doppler figures before you go out: on a 70cm downlink the shift runs to several kilohertz across a pass, and knowing you have to chase it downward is what separates a contact from ten minutes of confusion. Take the .ics so the reminder finds you, and be listening a minute before AOS, because the first thing you hear is usually somebody already in the middle of a call.
Frequently asked questions
Why is the pass table empty?
Because it does not know where you are yet. Type your locator into the box above the map, or use the locate button, and the passes appear straight away. Nothing is predicted until you provide it, which is why there is no default: a pass list for the wrong grid square is worse than no pass list.
Is my location sent anywhere?
No. Your locator is kept in your own browser and the orbital arithmetic runs on your device. The server only ever hands out the orbital elements, which are the same for everybody. Nothing about where you are leaves the machine you are reading this on.
Where do the orbits come from and how old are they?
From Celestrak, fetched on a schedule and cached on the site rather than downloaded by your browser. The line at the top of the page says how old the current set is. A day or two old is fine for FM work; once elements are a week old the predicted times start to drift by seconds and then minutes.
Which column tells me whether a pass is worth working?
Max el, before anything else. It is how high the satellite climbs in your sky at its best moment, and it decides whether you are working through a short clean path or a long slanting one full of houses and trees. Below about ten degrees, expect a brief and difficult pass.
What does the slider under the map do?
It moves the whole map forward by up to ninety minutes, footprints and all, so you can see where a satellite will be when it rises rather than where it is now. It stays where you leave it, which makes it easy to line up two satellites that overlap.
What is in the Downlink and uplink column?
The published frequency pair for that satellite. It is the starting point, not the frequency you will end up on: open a satellite from the table and its own panel shows the Doppler shift across the pass, which on a 70cm downlink can run to several kilohertz between AOS and LOS.
What does the Calendar button give me?
A standard .ics file for that pass, so it lands in whatever calendar you already use with the rise time, the duration and the maximum elevation in the entry. Useful for the one good pass in the evening that you would otherwise miss.
Why are some satellites I know missing?
The list is a curated set of amateur satellites with working transponders rather than the whole orbital catalogue, so anything without an active amateur payload is left out. If one you use is missing, or one in the list has gone quiet for good, tell me and I will change it.