Looking up at the starry sky in winter night, you will see many shining stars, which constellation is the most conspicuous.

Orion (seven bright and orderly stars, Orion nebula);

Taurus (Pleiades, the famous crab nebula);

Auriga (a prominent pentagon);

Gemini (neat rectangle);

Canis major (Nanhesan is very bright);

Canis Canis (Sirius has the highest brightness in the whole day, and another arrow shoots Sirius, the nine planets in the northwest);

The main stars of these six constellations form a striking hexagon, which is called the Winter Diamond. If you don't know these six constellations, and you say you know astronomy, I'm afraid no one will believe you.