Altitude The angular elevation of an object above or below the horizon.

At this instant, the time on the clock is recorded as well as the angular elevation of the star.

These angular elevations are faced with variegated granite.

At latitudes within 9 degrees of either pole, as the sun's angular elevation difference is less than 18 degrees, twilight can last for the entire 24 hours.

However, at latitudes closer than 9 degrees to either Pole, the Sun cannot rise above the horizon and go more than 18 degrees below it on the same day on any date, so this type of twilight cannot occur as the angular elevation difference between solar noon and solar midnight is less than 18 degrees.