Somnium is asteroid #3258 and also known as 1983 RJ. Somnium was discovered by the Swiss astronomer Paul Wild at the Zimmerwald Observatory. Somnium’s orbit is characterized by a semi-major axis of 2.21 Astronomical Units, an eccentricity of 0.20, a period of revolution of 1 198 days, and an inclination of 7.6 degrees.

Somnium is named after Somnium, sive opus posthumum de astronomia lunaris (The Dream, or Posthumous Work on Lunar Astronomy), which is a short story by Johannes Kepler. It was published by his son Ludwig Kepler four years after Johannes Kepler’s incarnation ended. Hence the term “Posthumous Work” in the title, which would be very strange if added by the author himself. Because you can see “mare” on the Moon, so the belief that there is life on the Moon had always existed until the age of space travels. Johannes Kepler’s fantasized in his Somnium about intelligent people on the Moon, who believed that the Moon is the center of the universe and the Earth is orbiting around the Moon. Thus Johannes Kepler tried to demonstrate Galileo Galilei’s principle of relativity and to prove the superiority of the heliocentric system.

The Latin word somnium means dream. But somnium can also mean wishful thinking, phantasma, delusion. The word somnium in the title of Johannes Kepler’s short story isn’t referring to a dream, which Johannes Kepler really had. It also isn’t referring to a certain wish or anything similar. Johannes Kepler simply tried to express that the story is a fictional story. So Somnium in an astrological chart represents fictional stories. Somnium most likely is relevant for people, who write fictional stories.