《宋书·志·卷二十三》
星辰向西运行，史官称之为逆行。 
星辰西行，史官谓之逆行。 
When the stars move westward, the historian calls it "retrograde motion".
<s>[INST] For each of the following sets of Classical Chinese and Modern Chinese sentences, provide an English translation that captures the essence of both: Classical: 星辰西行，史官谓之逆行。  Modern: 星辰向西运行，史官称之为逆行。  [/INST] When the stars move westward, the historian calls it "retrograde motion".</s>
For each of the following sets of Classical Chinese and Modern Chinese sentences, provide an English translation that captures the essence of both: Classical: 星辰西行，史官谓之逆行。  Modern: 星辰向西运行，史官称之为逆行。
user
When the stars move westward, the historian calls it "retrograde motion".
assistant