What is the difference between nautical and civil twilight?
Quick Answer: Civil twilight occurs when the sun is between 0° and 6° below the horizon, providing enough natural light for outdoor activities without artificial lighting. Nautical twilight happens when the sun is between 6° and 12° below the horizon, making the horizon faintly visible at sea, but it's darker than civil twilight.
Civil twilight is the brighter phase right after sunset or before sunrise. You can still see well enough outside without turning on lights. It’s when most daily outdoor activities happen.
Nautical twilight is darker. The sun is farther below the horizon, so the sky dims and the horizon line becomes hard to spot. Sailors use this time to navigate by the stars since the horizon is still visible, but it's too dark for normal vision.