《北史·列传·卷六十二》
《尧典》说： 白昼短昴星出，正是仲冬 。
《尧典》曰： 日短星昴，以正仲冬。 
The "Yao Dian" mentions: The daylight hours are short and the Pleiades appear, it is mid-winter.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 《尧典》曰： 日短星昴，以正仲冬。  [/INST] The "Yao Dian" mentions: The daylight hours are short and the Pleiades appear, it is mid-winter.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 《尧典》曰： 日短星昴，以正仲冬。
user
The "Yao Dian" mentions: The daylight hours are short and the Pleiades appear, it is mid-winter.
assistant