Introduction to Ursa minor

Observation characteristics

Connecting the seven bright stars in Ursa major can form a bucket similar to the Big Dipper in Ursa major, so these seven stars are also called Ursa minor. Bucket handle begins with Alpha Ursa minor, which is now the Polaris, indicating the north celestial pole. Polaris can be found by drawing a straight line from the two stars β (Tian Xuan) and α (Shu Tian) in the constellation Ursa Major and extending it to five times the distance between the two stars.

Appearance characteristics

The main bright star in the connecting star map is not so much the image of a bear as the appearance of a little Beidou. This "Big Dipper" in Ursa minor is much smaller than the Big Dipper in Ursa major, and it is far less eye-catching.

Polaris and the Earth's Rotation Axis

The position of the earth's rotation axis in the sky is very stable, so people define the direction of the earth's rotation axis in the sky as south and north. Polaris is just in the direction of the earth's rotation axis, so in ancient times, when people sailed in the sea and trudged in deserts, forests and wilderness, they always turned to it to indicate the direction. People worship it so much that China even regarded it as a symbol of ancient emperors. Even in today's highly developed science and technology, Polaris still has very important applications in astronomical measurement, positioning and many other aspects.

In fact, Polaris is not entirely in the North Pole. It is far from the North Pole 1, but there is no other star closer to the North Pole, so it is regarded as the nearby North Pole. If we stand at the north pole of the earth, the Polaris is directly above us. In other parts of the northern hemisphere, people see that Polaris is always in that position due north. Moreover, due to the rotation and revolution of the earth, the constellations in the northern sky seem to revolve around the North Star every day and every year. In particular, the spoon mouth points to the big dipper of Polaris, and it never tires and never stops. The ancients in China were deeply touched by this and wrote in the Book of Changes, "Heaven is healthy, and gentlemen are constantly striving for self-improvement." If it makes sense.