Part of the astronomers' duties was to predict eclipses so the emperor could prepare for them in advance. A predicted eclipse which failed to occur was considered a good omen, while an unexpected one was looked at with dismay.

They were afraid of strange events in the heavens. In their cosmology, celestial events were categorized into periodic and nonperiodic, and the nonperiodic events were the most frightening. The army of the Minamoto clan retreated from battle upon witnessing a solar eclipse, an event the Japanese considered nonperiodic. As you may know, Death Moon Circus enter Earth during an predicted solar eclipse, but a second unpredicted one began Neherenia's curse.

The Japanese divided the sky into 28 lunar mansions, similar to signs of the zodiac, showing the importance of the moon in their cosmology. Taken from A Short Description of Ancient Japanese Culture and Cosmology by Mitch Stoltz