Autor: Tau'olonga
Fecha: julio 2006
Licencia: Creative Commons. Puede copiarse, debe mencionarse al autor
Descripción: Arco diurno del Sol, durante el solsticio de veranp, vistos en el cielo desde el polo norte. Lo mismo se ve en el solsticio de invierno en el polo sur.

"The day arcs at the pole. At the time of the summer or winter solstices, the Sun is 23.44° degrees above or below the horizon respectively, irrespective of time of day. Whilst the Sun is up (during summer months) it will circle around the whole sky, appearing to stay at same angle from the horizon, therefore the concept of day or night is meaningless. The angle of elevation will gradually change on an annual cycle, with the Sun reaching its highest point at the summer Solstice, and rising or setting at the Equinox, with extended periods of twilight lasting several days after the autumn equinox and before the spring equinox."