<Ol> <Li> From the Earth, the Sun appears as a disc rather than a point of light, so when the centre of the Sun is below the horizon, its upper edge is visible . Sunrise, which begins daytime, occurs when the top of the Sun's disk rises above the eastern horizon . At that instant, the disk's centre is still below the horizon . </Li> <Li> The Earth's atmosphere refracts sunlight . As a result, an observer sees daylight before the top of the Sun's disk rises above the horizon . </Li> </Ol> <Li> From the Earth, the Sun appears as a disc rather than a point of light, so when the centre of the Sun is below the horizon, its upper edge is visible . Sunrise, which begins daytime, occurs when the top of the Sun's disk rises above the eastern horizon . At that instant, the disk's centre is still below the horizon . </Li> <Li> The Earth's atmosphere refracts sunlight . As a result, an observer sees daylight before the top of the Sun's disk rises above the horizon . </Li> <P> In sunrise / sunset tables, the assumed semidiameter (apparent radius) of the Sun is 16 arcminutes and the atmospheric refraction is assumed to be 34 arcminutes . Their combination means that when the upper limb of the Sun is on the visible horizon, its centre is 50 arcminutes below the geometric horizon, which is the intersection with the celestial sphere of a horizontal plane through the eye of the observer . </P>

Whats the point of it comes at night