Page 767

[Alexandr Korol]

First — the demonstrative function, this is the main type: it showed the geometry of the
sky, the movement of the stars, sunrises, sunsets, the seasons, the length of the day.
Second — the observational: for measuring the coordinates of the heavenly bodies,
that is, the altitude and azimuth. Third — the educational: in the universities, with its
help, they explained spherical astronomy and trigonometry. Fourth — the astrological,
symbolic: it connected the macrocosm, that is, the Universe, and the microcosm of the
human being. By rotating the sphere, one could model the daily movement of the sky,
the Primum Mobile, the annual movement of the sun along the ecliptic, and so on. It
ideally illustrated the medieval cosmology that we spoke about earlier.

Today, armillary spheres are popular decorative objects in gardens, museums, and as
scientific replicas. They remain a symbol of astronomy, science, and the harmony of the
cosmos. Many modern versions work as sundials. This is not merely an instrument, it
is a whole philosophical model of the world, which joined observation, mathematics,
theology, and art.

The spirits put the emphasis on my mentioning in the book, without fail, what
De sphaera mundi is.

This is a fundamental medieval treatise on astronomy, written around 1220 by the
English scholar, monk, and lecturer at the University of Paris Johannes de Sacrobosco,
also known as John of Holywood. This is one of the most influential astronomy textbooks
in Europe before the Copernican revolution. The treatise consists of four books: on the
sphere as a whole, on the celestial circles, on the rising and setting of the luminaries,
and on eclipses. The first book proves the sphericity of the Earth through observations
of ships, of stars at different latitudes, and of lunar eclipses. The second describes the
celestial circles and the climatic zones. The third explains the visible movement of the
luminaries depending on the latitude. The fourth examines the seven planets, including
the Sun and the Moon, their orbits and the causes of eclipses.

This is all highlighted for me, I read about all of this. In my plans in the near future
is to watch the film “John Carter.” In my plans is to read once more — although
I know what Mars is, why the planet is called that. I’m even curious to record
this path. How do I understand what Mars is? For now, I still haven’t opened