You absolutely see star trails on iphone night mode photos when setting exposure to 10s or more. For aurora, 10s is way too much though, 1-3s seems right and is

You absolutely see star trails on iphone night mode photos when setting exposure to 10s or more. For aurora, 10s is way too much though, 1-3s seems right and is what the iphone allows to do when not on a stable surface or tripod.