Twilight is the light before sunrise or after sunset. There are 3 types of twilight:
- Civil twilight, which is when the Sun is between 0 and 6° below the horizon. The brightest planets and stars appear.
- Nautical twilight, which is when the Sun is between 6 and 12° below the horizon. The sky is almost completely dark, but there is still a glow where the Sun has set.
- Astronomical twilight, when the Sun is between 12 and 18° below the horizon. Although the sky is completely dark, very dim and distant objects are not visible yet.