officelkp.blogg.se

Greek sundials typically used a point-like object, called the nodus, as the reference marker.

The next day, if the sun has moved north or south because of the slowly changing seasons, the path the shadow traces moves a little bit above or below the previous days path. In the tropics (between the Tropics of Capricorn and Cancer), some paths are to the north while some are to the south. The red lines show the position of the sun along each arc at the labelled hour of the day.įor a location in the northern hemisphere north of the tropics, the sun paths would be curved the other way, passing south of overhead. The sun is lowest in the sky to the north, and visible for the shortest time, on the June solstice (the southern winter), while it is highest in the sky and visible for the longest on the December solstice (in summer). The following diagram shows the path of the sun across the sky for different dates, for my home of Sydney (latitude 34S). Midway between the solstices, at the March and September equinoxes, both hemispheres receive the same amount of sun. Half a year later at the December solstice, the sun is on the other side of the Earth, making it summer in the south and winter in the north. At the June solstice (roughly 21 June), the northern hemisphere is maximally pointed towards the sun, making it summer while the southern hemisphere has winter.