The ancient Chinese made careful observations of celestial bodies and phenomena for uses in astrology and prognostication. The astronomer Gan De from the State of Qi during the Period of Warring States was the first in history to realize that sunspots were a genuine solar phenomena, while the first precisely dated sunspot observation in China occurred on May 10, 28 BCE during the reign of Emperor Cheng of Han. The Miscellaneous Readings of Cosmic Patterns and Pneuma Images manuscript illustrates in writings and ink drawings approximately three-hundred different climatic and astronomical features including clouds, mirages, rainbows, stars, constellations, and comets. Another text from the same site reports the times and locations of the rising and setting of planets at night from the years 246–177 BCE. The Han Chinese noted the passage of the same comet seen in Persia during the birth of Mithridates II of Parthia in 135 BCE, the same comet the Romans observed close to the assassination of Julius Caesar in 44 BCE, Halley's comet in 12 BCE, and a supernova in 185 CE. The history books Records of the Grand Historian and Book of Han provide numerous detail for various comets, such as their position in the sky, direction they were moving, the length of time they were visible, their color, and their size. The Han Chinese also made star catalogues, such as historian Sima Qian's A Monograph on Celestial Officials and Zhang Heng's 2nd-century CE star catalogue which featured roughly 2,500 stars and 124 constellations.