Ask the photographer how to show the spiral white curve in the night sky (or dusk).

This is the trajectory of the star's movement. You need a tripod to fix the camera, and use a wide-angle lens to narrow the aperture, usually at 16 or 22.

ISO is set to 100, and then to door B, which takes about 15 minutes. You need to shoot multiple shots in a row, and a trajectory like this takes about 3 hours.

In this way, a plurality of photos are formed by ps synthesis.

If the exposure time is kept too long, it will cause overexposure of the night sky and foreground.