Unexpectedly good.
I accidentally purchased this while searching for an aurora app so had zero expectations. As a ‘let’s see what happens’ joke I tried photographing a very dull aurora on a flight from Calgary to White Horse by holding the phone against the window and blocking out ambient light with a neck pillow, on a six second exposure. Insane as that sounds, to our utter amazement and delight we ended up with a semi decent (albeit grainy) photo clearly showing a bright green aurora.