The Sky Calendar will display three degrees off twilight, civil- nautical and astronomical. There is still enough light to read and only the brightest stars are visible.
Many stars are visible and the horizon is barely visible.
The duration of twilight is a result of the Suns path with respect to the horizon. Near the equator the twilight is always of short as the Sun disappears almost vertical straight down below the horizon. The farther North or South you go from the equator, the shallower is the angel the Sun travels as it disappears below the horizon and twilight lasts longer.