Schiaparelli's observations of Mercury. This drawing was made by the Italian astronomer Giovanni Schiaparelli (1835-1910). In the 1880s he mapped the planet more accurately, and suggested that Mercury's rotational period was 88 days, the same as its orbital period. From 1862, Schiaparelli was Director of the Milan Observatory for forty years. He is most famous for his observations of Mars, and also showed that meteors follow cometary orbits.