The front of the moon is characterized by a large area of darkness, which is generally believed to be the 17th century astronomers (especially Giovanni Battista Rijoli and Francisco Maria Grimaldi ）First name these areas after the sea. Although it was later discovered that there was no water on the moon, the names of these seas were still used. The brighter areas are considered land, or more commonly referred to as highlands.
When the image of the moon is drawn as a map, the usual representation is that the north is on the top and the west is on the left. Astronomers usually invert the lunar surface so that it faces south up to fit the upside down image of most telescopes.
When you are on the moon, you should pay attention to the east-west direction on the moon, usually you will not pay attention. But we are on the earth, looking at the moon in the sky from the earth, so the east and the west will be opposite. Therefore, when using coordinates on the moon, it is necessary to indicate whether to use Geography (or more specifically Lunar ）Coordinate or use astronomy Coordinates of. The actual position of the moon seen by the observer in the sky or on the horizon depends on the geography of the observer latitude Several typical cases will be considered in the following description: At the North Pole: if the moon can be seen, the closer to the North Pole, the closer the moon will be to the horizon.
Mid latitudes in the Northern Hemisphere (North America, Europe and Asia): when the moon rises from the east, the northeast edge of the moon（ Perilous sea ）Upward; When reaching the south and reaching the highest point, the north of the moon is above; When the west sank, the northwest edge（ Rainy Sea ）Above. At the equator: when the moon rises from the east, the north-south axis is parallel to the horizon, Abundant Sea Above; About 12.5 hours later, when the west sank, the north-south axis was still parallel to the horizon, Storm ocean Is the last area to sink below the horizon. When the moon reaches the highest point or zenith The direction of the lunar coordinates is consistent with that of the Earth. Mid latitude in the southern hemisphere (South America, South Pacific, Australia, South Africa): when the moon rises from the east, the southeast edge（ Shenjiu Sea ）Upward; When reaching the highest point, the position is in the north, while the south is upward; When it sinks to the west, the southwest edge（ Wet sea ）Face up. At the South Pole: The moon behaves similarly to the North Pole, but it faces up from the south
