According to the Beijing News, based on data obtained by Chang'e-1, Chinese scientists have measured the vertex and nadir of the moon accurately for the first time, and found that the moon is more spherical than the Earth.
Ping Jinsong, chief technical designer of the subsystem for the satellite monitoring system VLBI, said on November 27, that "the shape of the moon is close to a perfect sphere." Comparing the oblateness of the moon, 1/963.7256, with the oblateness of the Earth, 1/298.257, the moon has been found to be more orbicular than the Earth.
On November 12, China revealed the complete image of the moon's surface based on the photographs taken by Chang'e-1. Currently, experts are carrying out elevation calibrations of the photographs using data from the laser altimeter so as to get a 3-D topographic map of the moon's surface. Ping also said that they had achieved a topographic model of the moon with the highest precision yet and the most accurate vertex and nadir of the moon for the first time using Chang'e-1's laser altimeter.
Ping said that since the nadir and vertex of the moon are located in the polar area and the back section of the moon, respectively, they cannot be seen from earth. The precision of comprehensive data achieved by Chang'e-1 is higher, and compared with international measurements; the deviation of the two points is reduced by about 200 kilometers. "The distance precision of other countries is generally more than 100 meters, but our model is precise to within 30 meters."
By People's Daily Online