《晋书·志·第三章》
占卜说： 牵牛座是日月五星起始的地方，彗星从遣裹出现，是改易纪元、称号的征象。
占曰： 牛者七政始，彗出之，改元易号之象也。
Divination said that the Cowherd constellation is the place where the sun, the moon, and the five planets originated. The comet appeared from the Cowherd constellation, which is a sign of changing the era and the title.
<s>[INST] Kindly elucidate the central themes in this passage in English: 占曰： 牛者七政始，彗出之，改元易号之象也。 [/INST] Divination said that the Cowherd constellation is the place where the sun, the moon, and the five planets originated. The comet appeared from the Cowherd constellation, which is a sign of changing the era and the title.</s>
Kindly elucidate the central themes in this passage in English: 占曰： 牛者七政始，彗出之，改元易号之象也。
user
Divination said that the Cowherd constellation is the place where the sun, the moon, and the five planets originated. The comet appeared from the Cowherd constellation, which is a sign of changing the era and the title.
assistant