Orbital Confusion

Paintings of this kind are often described as representing the "gola". This is a Sanskrit word that is usually not translated into Tibetan in texts on astronomy. It basically means circle, and in his short text on gola, Buton Rinchen Drup describes three types of such circle. The first he calls the normal "circle of the world", which is the upper surface of the disks of earth and water that are considered to constitute our world. The surface of the disk of earth beyond the Sīta mountains holds the main twelve continents and the oceans that separate them. Beyond lies the great salt ocean that rises up from the lower disk of water. It is these two areas together that Buton refers to as the "circle of the world".

The other two circles are essentially the same: the "circle of the (zodiac) signs" and the "circle of the lunar mansions". These refer to the apparent orbit of the Sun, which would be called the ecliptic in modern terms. It is considered in the Kālacakra system that the Sun and the stars of the zodiacal signs and lunar mansions rotate around the central Mt. Meru once every day, bringing the change of day and night to the various continents, and that throughout the year, the Sun moves through the zodiac signs, and a change in orbital disposition brings about the changing of the seasons.

Both of these two main types of gola are depicted in pictures of this kind. The basic gola are described very briefly in the Kālacakra Tantra and its commentary the Vimalaprabhā. Like many such descriptions in this literature, they are so brief as to be open to multiple interpretation, and there are approximately half a dozen different systems described in the Tibetan literature. The most common of these is known as the "Twisted ball of string" .

Credits: www.kalacakra.org/phyinang/golconf.htm