Astronomy was another topic of interest close to Čiurlionis' heart. He constantly delved deeper into the subject to find new information. At the turn of the twentieth century, the work of Camille Flammarion, published for the general public, was especially popular. Čiurlionis' perception of the world was also influenced by the astronomer's explorations of celestial movements. During his travels, the artist loved to observe the night sky: “The moon has receded, and the stars have come out in all of their brightness to light up the most magical part of the sky: Orion, the Pleiades, Sirius, this is California, according to Flammarion. I am reminded of the road back from out trip – the sky was much like this one, perhaps even more beautiful. At such moments it is good to forget where you are going and where you are coming from, and to see things with an infant's eyes. <...> If only one could always live with eyes wide open to everything that is beautiful, and not to wake and return to oneself,” (Letter to B. Wolman, Prague, 1/09/1906).

The maturity of the cycle “Zodiac”, evidenced by the fluid forms of expression, the monumentality of the compositions, makes this an epic collection of paintings. The main idea behind this cycle is not to simply illustrate the signs themselves, but also to track the movement of the sun across the sky and along the path of the Zodiac. “Čiurlionis uses artistic devices of expression to speak about everything. The battle between light and darkness in the path of his Sun is not an abstraction or a banal allegory. This is a very real, cosmically perceived fluctuation of day and night, the birth and death of natural phenomena, the harmony, conflicts, celebrations, and enigmas of the great happenings of the Universe,” (Landsbergis, V. Čiurlionio dailė. Vilnius: Vaga, 1976, 177).