This rare form of aurora is called a proton arc, and it’s the second one that I’ve photographed this year. The first was like a laser beam. This one hung out for a long time. You can also see an iridium flare in this shot. An iridium flare is caused by an Iridium satellite. It has a highly reflective panel about the size of a door that catches sunlight and causes a bright flare in the sky.