What is Find Satellites?⌗
It’s a tool to help you find satellites. It can show you where they are around the globe, or from your location on Earth.
How will Find Satellites help me find satellites?⌗
Firstly, it plots the positions of 70+ significant satellites such as the ISS, geostationary satellites, cloud and weather monitors and of course the Moon. On top of that, it tracks the current 400+ Starlink satellites.
These positions are plotted relative to the Earth, based on a longitude, latitude and radial distance. So if a satellite were to be directly overhead at your particular geoposition, there would be a straight line running from the center of the Earth, through you, up to that satellite.
Each satellite is accompanied by a line showing its current trajectory, within a two hour window, more or less. A line also joins the satellite’s position in space to its overhead position on the Earth, showing in green when in your line of sight, and red when not.
The first time you use the app, it should request permission to use your device’s location. This is so that your position can be plotted on the globe, and used to calculate satellite visibility.
The theoretical visibility of satellites is determined by whether a straight line can be cast between your position on the Earth’s surface and the satellite without intersecting the curvature of the Earth. At the moment, this may not reflect actual visibility as nearby hills, trees and nefarious malcontents may not be fully taken into consideration.
Data available for each satellite will generally span around 2 hours, so you will see each satellites positions plotted as a path, showing the recent past and imminent future, generally an hour either way, give or take half an hour. When a satellite is selected, an arrow on the path will indicate direction of travel.
The app shows a row of satellites matching your current filter selection. Possible selections include currently visible satellites, near-earth satellites, far-earth satellites, geo-stationary satellites, and so forth.
Why do some satellites not show path information?⌗
One explanation is that you’re looking at the geostationary satellites. Since these move at the same speed as the Earth, they will always appear relative to the same latitude and longitude point. The other possibility is that you’re looking at the Starlink satellites. If the app plotted all the Starlink paths, the Earth would just look like a giant ball of string.
Why are some satellites shown as blue dots with smaller text?⌗
They are all Starlinks. I’ve attempted to render them in such a way as to not overpower everything else, hence the lack of paths, smaller text labels and so forth.
Where is the satellite position data coming from?⌗
It comes from a feed provided by NASA, and also Celestrak. The NASA feed contains verified, historical data, and also predicted future data. The Celestrak feed contains TLE data for all available Starlinks. Find Satellites refreshes its data every half an hour, so that as satellite positions are updated in real time, they should be more than accurate enough for any purpose you are likely to be using this application for.
Something broke, when will you fix it?⌗
I’ve probably noticed, and so hopefully soon.
If you find the web app that this blog is hiding inside at all useful or interesting, you are more than welcome to Buy me a Coffee. Without coffee, no staying up coding until 4am. You can also Find me on Twitter for free, of course.