Twilight is the period of time when the sun is still visible below the horizon, but its light is no longer strong enough to illuminate the sky. This period begins at sunset and ends when the sun is 18 degrees below the horizon. During twilight, the sky is often a deep blue or purple color, and stars may begin to appear.
Dusk is the period of time when the sky is completely dark, but there is still some light from the sun in the atmosphere. This period begins when the sun is 18 degrees below the horizon and ends when the sun is 22.5 degrees below the horizon. During dusk, the sky is often a dark gray or black color, and stars are more visible.
So, the main difference between twilight and dusk is the amount of light in the sky. Twilight is the period of time when there is still some light from the sun visible, while dusk is the period of time when the sky is completely dark.
