The appearance time of the big dipper.

For the mid-latitude areas in the northern hemisphere, the Big Dipper can be seen almost all night.

The above picture is a schematic diagram of the position of the Big Dipper, which is about the position of the Big Dipper at 8 o'clock or 9 o'clock every season in the area of 40 north latitude. It can be seen that even in autumn and winter, when the position of the Big Dipper is the lowest, it is basically above the horizon.

At the turn of winter and spring, after sunset, the Big Dipper is located about 30 east of the northern part of the sky, pointing vertically to the northeast. At midnight, it is located in the northern sky, and bucket handle points to the southeast; Before dawn, it is located to the west of 30 north latitude, and bucket handle points to the southwest.