Question: the time of day just after the sunsets
Answer: Sunset is distinct from twilight , which has three phases , the first being civil twilight , which begins once the Sun has disappeared below the horizon , and continues until it descends to 6 degrees below the horizon ; the second phase is nautical twilight , between 6 and 12 degrees below the horizon ; and the third is astronomical twilight , which is the period when the Sun is between 12 and 18 degrees below the horizon .