Along with his colleague Wei Pu in the Bureau of Astronomy, Shen Kuo planned to plot out the exact coordinates of planetary and lunar movements by recording their astronomical observations three times a night for a continuum of five years. The Song astronomers of Shen's day still retained the lunar theory and coordinates of the earlier Yi Xing, which after 350 years had devolved into a state of considerable error. Shen criticized earlier Chinese astronomers for failing to describe celestial movement in spatial terms, yet he did not attempt to provide any reasoning for the motive power of the planets or other celestial movements. Shen and Wei began astronomical observations for the Moon and planets by plotting their locations three times a night for what should have been five successive years. The officials and astronomers at court were deeply opposed Wei and Shen's work, offended by their insistence that the coordinates of the renowned Yi Xing were inaccurate. They also slandered Wei Pu, out of resentment that a commoner had expertise exceeding theirs. When Wei and Shen made a public demonstration using the gnomon to prove the doubtful wrong, the other ministers reluctantly agreed to correct the lunar and solar errors. Despite this success, they eventually dismissed Wei and Shen's tables of planetary motions. Therefore, only the worst and most obvious planetary errors were corrected, and many inaccuracies remained.