"The stars are divided into wings, and the earth meets Lu Heng" means that the position in the sky belongs to the wing, which separates the two stars, and the position on the ground connects Hengshan and Lushan.
The ancients used to use the stars in the sky to correspond to the areas on the ground, which was called "one star and one place". According to Tian Wenzhi, it belongs to Wudi, which is the dividing line between Yangzhou and wuyue, and the two stars are adjacent. Wings and chariots are the names of stars, belonging to 28 huts.
Encyclopedia quotes a sentence from Historical Records: "Wing, Qi and Jingzhou". Jingzhou here is one of the ancient "Kyushu"-between Jingshan and Hengshan.
Jingshan is in Nanzhang County, Hubei Province, and Hengshan is in Hengyang City, Hunan Province. From the map, Nanchang is just sandwiched between these two places, which also coincides with the author's saying that "the stars are divided into two wings and the ground meets Lu Heng".
Extended data:
The reason why Wang Bo wrote preface to Wang Teng-ting;
In the autumn of 675, Wang Bo went to Jiao Jiao to visit his father. When I passed Nanchang, I was just catching up with the Governor Yan Xinjian Pavilion, and the Double Ninth Festival was held in the pavilion.
When Wang Bo visited, the satrap of Yan heard of his reputation and invited him to a banquet. The purpose of this banquet is to brag about the talent of his son-in-law, Meng, and let his son-in-law prepare a preface in advance and show it to everyone as an improvisation during the dinner.
At the banquet, the satrap of Yan asked people to take out paper and pen, and for a pretence asked them to preface the grand event. Everyone knew his intention, so they refused to write, but Wang Bo, a young junior in his twenties, didn't refuse. He picked up a pen and paper and wrote in public.
Yan Dudu's boss was unhappy, so he brushed his clothes and went to settle accounts. When he heard Wang Bo write at the beginning that "Nanchang is the old capital and Hongdu is a new house", the governor said: This is just a cliche.
I heard that "the stars are divided, and the ground meets Lu Heng". I hesitated and said nothing. When he heard that "the sunset and the lonely Qi Fei grow into the same color", the governor had to gasp in admiration: "This is a genius and should be immortal!"
Baidu Encyclopedia-Preface to Wang Teng Pavilion