How EQUiSat’s Flashing Works
Seeing EQUiSat isn’t quite as easy as just looking up while it’s passing overhead. The satellite’s four LEDs are only on one face of the satellite, and point in a very specific direction as described below. There can also be long periods of time where the satellite isn’t flashing at all. However, this makes it that much more exciting to search for EQUiSat!
Can I see it where I am?
To understand how to see EQUiSat, you need to understand what direction it faces. The satellite was designed to act like a magnet (it has a magnet inside it), such that its LEDs will point along the magnetic field lines of the earth, towards the magnetic North Pole. It points this way no matter what direction it is moving.
Over most of the planet, these field lines are parallel to the earth’s surface, but as the satellite gets closer to the magnetic North Pole, these lines (and the LEDs) point down into the ground towards the earth’s core.
This means that the closer you get to the magnetic North Pole, the better you’ll be able to see EQUiSat, because it will be pointing more towards the ground. However, it should be visible even at low latitudes such as 10 degrees north. The fact that EQUiSat faces to the north also means that you’ll need to be north of it to see the LEDs. So keep an eye out during passes that go south of you!
The map below shows the inclination of the earth’s magnetic field around the world. The angle given is the angle you should be looking up at to see EQUiSat. On our apps, you can compare it to the “maximum elevation” of a pass to the south of you to where you should look to see the flash.
How bright is it?
The LEDs were designed to produce an apparent magnitude of 3 on a good pass, making them a little dimmer than the North Star. Here is a good list of the apparent magnitude of other objects to get a sense of EQUiSat’s brightness, but keep in mind it only lights up briefly.
When does it flash?
When it’s set to flash, EQUiSat performs a “flash burst” every minute. During a burst it flashes three times for a tenth of a second, with each flash one second apart.
The satellite in normal operation will switch between two states: “IDLE FLASH” and “IDLE NO FLASH.” During IDLE NO FLASH, the satellite will work on charging its LiFePO4 batteries. Once they’re almost full, it will switch to IDLE FLASH and will keep flashing until the batteries get low and it switches back. It tends to flash for several hours before needing to recharge over the course of about a week.
