[1] To allow more accurate astronomical observations and recordings, Shen Kuo improved the technical designs of the rotating armillary sphere, the gnomon, the clepsydra clock, and the sighting tube.
[2] Shen Kuo calibrated the standard diameter of the sighting tube's width, hence allowing the observation of the pole star indefinitely (which had shifted since the time of Zu Geng in the 5th century).
[3] Wei and Shen's work was deeply opposed by the officials and fellow astronomers at court, who were offended by their insistence that the coordinates of the renowned Yi Xing were inaccurate.
[6] Although correcting the lunar error was a success, the other ministers and officials eventually dismissed Wei and Shen's recorded course plotting of planetary motions, while the court relied upon the inefficient and older model.
[8] This meant that only the very worst errors were corrected for planetary motion, and in his disappointment, Shen wrote, "How sad that the backbiting of that bunch of calendar-makers could have kept him from bringing his art to fruition!