From Ars Technica:

Late Friday night, two sounding rockets launched from a small spaceport in northern Norway. The two skinny rockets soared to an altitude of 320km, and along the way each released a visible gas intended to disperse through and illuminate conditions inside the aurora borealis. Some of the resulting images were stunning.

This NASA-funded AZURE mission, which stands for Auroral Zone Upwelling Rocket Experiment, is one of a series of sounding rocket missions launching over the next two years as part of an international collaboration known as "The Grand Challenge Initiative – Cusp." The goal of these flights is to study the region where Earth's magnetic field lines bend down into the atmosphere, and particles from space mix with those from the planet.

Friday night's mission involved two Black Brant XI-A rockets, a three-stage sounding booster with a long heritage dating back to Canadian military research in the 1950s. The Black Brant rockets launched within two minutes of one another from the picturesque Andøya Space Center in Norway, beginning at 22:14 UTC Friday.