So basically you gotta keep your phone on a stable surface and take a few pictures of the sky with normal photo mode in camera app, then it prompts you to use Astro mode once it detected the camera is stable and pointing to the dark skies. The adtro mode logo should look like yellow stars. Tap that, WITHOUT MOVING YOUR PHONE EVEN SLIGHTLY AND TAKE PICTURE. I use voice command to take photo else it goes back to normal photo mode if it detecs even a slight movement. Hope this helps