How to observe the Big Dipper?

Before observing, you need to determine the latitude of your observation site. Because the horizon height of Polaris is equal to the geographical latitude of the observer.

After determining the latitude, when night falls on a sunny day, you face the north, look horizontally, look up, and the angle is just the degree of latitude (if you are at 45 degrees north latitude, you have to raise it by 45 degrees, how to measure this angle, hehe, find a protractor if it is simple). At this time, there should be a bright star in the center of your field of vision relative to the stars around it. This star is called Alpha Ursa minor, which China traditionally called "Gouchen II". It is also commonly known as Polaris (the north pole of the sky is the direction pointed by the earth axis). In fact, this star is not in the true position of the North Pole of the sky, but it is the bright star closest to the North Pole of the sky at present. Due to precession, Vega will become the North Star after 12000. Polaris never sets. If there is a total solar eclipse during the day, you can see it. Another thing to understand is that in the northern hemisphere, when you observe the starry sky, all the stars revolve around the Polaris (you can think about why? ), which is why the North Pole should be located first when using astronomical telescopes.

Let's talk about the Big Dipper again. The Big Dipper consists of seven stars and belongs to Ursa major in modern astronomy. In fact, these seven stars are relatively easy to identify in the northern sky. The four stars in the hat are near the North Pole, and the three stars in the bucket handle are outside. Most people find the Big Dipper first and then the North Star without tools. As mentioned above, the stars in the northern hemisphere rotate clockwise around the north pole of the celestial sphere, so when you observe the Big Dipper at different times, its position will be different. Do you remember an old saying in China: bucket handle refers to the east, and the world is spring; Bucket handle guide, the world is summer; Bucket handle refers to the west, and the world is autumn; The barrel handle refers to the north, and it is winter all over the world. That is to say, at dusk in spring, you can see that the handle of the bucket points to the east, and so on. At this time, you can find the bucket spoon in the direction of bucket handle. If your latitude is high enough, you can also see it all night (of course, the Big Dipper may be above your head for a while).

Regular observation can increase experience, and it is meaningless to talk on paper. Let's get out of here.