Interpreting Auroral Activity from Space

These images are derived from the very sensitive camera's on the polar orbiting NOAA-21, NOAA-20 and NOAA Suomi spacecraft. Spacecraft data is processed in near real-time by Solar Terrestrial Dispatch and presented here for public consumption.

The spacecraft are aligned in a train over the polar regions and are separated by about 25 minutes from each other. It takes ~90 minutes to complete one pass around the Earth.

The image above was taken during quiet conditions when very little auroral activity was visible except over the higher latitudes as annotated.

The image above was taken in the first few hours following the arrival of the strong coronal mass ejection of 11/12 November 2025.

Note, in particular, how the shape of the blue line changes into a wedge-shape. The area inside the wedge represents astronomically dark observing conditions. Outside the wedge, the moon has risen and might interfere with observations by brightening the sky.

Later in the morning of 12 November, the overnight satellite passes show the extent of the northern lights activity across North America.

The red and blue lines are always plotted at the time of the latest satellite pass shown at the bottom (13:49 UTC, or 8:49 am EST).

Remember that the overnight satellite passes are still visible, even though the Sun has risen (or is rising) over North America. Later in the day, the daylight pass of the spacecraft will erase the overnight images.