How to judge the direction of time according to sunlight and moonlight

On a clear day, you can easily know the east and the west according to the sunrise and sunset, so you can judge the direction, but it can only be a rough estimate. There are several more accurate judgment methods: 1. Watch direction finding "time is half that of the sun, 12 refers to the north". Generally, you can quickly identify the direction between 9 am and 4 pm, and use half the time to refer to it. 12 is the north, such as 14:40 in the afternoon, half of it is 7:20, and the time points to the sun, so 12 refers to the north, or put the watch flat, the hour hand points to the sun, and the extension direction of the hour hand and the bisector of 12 are the north; Or put a watch, put a stick in the center of the watch to turn the watch, so that the shadow of the stick coincides with the hour hand, and the bisector between the hour hand and 12 is north.

It must be noted that (1) when judging the direction, the watch should be flat; (2) In the area between 20 30' south latitude, it is not suitable for use around noon, that is, every 15 plus 1 hour in the east and every 15 plus 1 hour in the west. The direction of the sun shadow is sunny, and a wooden stick is erected on the ground. The shadow of the stick moves with the position of the sun. These shadows are the shortest at noon, the connecting line at the end is a straight line, and the vertical line of the straight line is the north-south direction. Draw a series of concentric circles on a piece of 50×50cm drawing paper, with the radius of concentric circles increasing by 1cm, nail them horizontally on a flat plate, and vertically insert a thin steel needle or needle with a length of 12- 15cm on the center of the circle. When the position of the sun changes, the endpoint of the shadow always intersects with the concentric circles. Draw these points, then connect two straight lines on the same circle, and connect the midpoint of these straight lines with the center of the circle. This connecting line is the north-south direction line, and the direction of the arc top is the north.

At night, you can judge the direction according to Polaris and Southern Cross.

1, Polaris: Polaris is located in the northern sky, and its exposed altitude angle is equivalent to the local latitude, so it can be found quickly. Usually according to the Big Dipper (Ursa Major) or the W Star (Fairy Queen). The Big Dipper is seven bright stars, shaped like a spoon. The place where the two β -α directions of the spoon extend about 5 times is Polaris. When you can't see the Big Dipper, you can look for the North Star according to the constellation W after Fairy. Cassiopeia consists of five bright stars, shaped like a "W" letter, and the distance between the opening direction and the opening width of the letter is about twice that of Polaris.

2. Southern Cross: In the area south of 23 30' north latitude, the Southern Cross is sometimes seen at night. It consists of four bright stars in the shape of a "cross", and at the lower right, four and a half times (no stars) of the connecting line between the two stars from γ to α is due south.