Rahu is planetary demon king who has home at the northern base of Mount Sumeru, the axis of rotation of celestial sphere. He was born with nine heads, nine hearts, four arms, a frog body with wide open mouth at the belly, and a serpent tail. He was born so giant with height more than one hundred twenty three thousand kilometers that when he stands the deepest ocean reach only up to his knees, and with one finger he can hide the sun or moon. When Rahu ascended to mount Sumeru from underneath the ocean to catch a glimpse of sky maidens, not able to see, he covers the sun with his right hand causing the solar eclipse.
During the time of Sakyamuni Buddha, Surya, the god of sun, took refuge in Buddha so as to save from Rahu. Buddha had to extend his size to overpower Rahu, for the latter was stubborn to comply the command. Rahu then fled for not being able to confront the magical strength of Buddha.
When Rahu hides the sun or moon, when earthquake happens, or during solstices or when year ends, we are advised to visualize Samantabhadra and recite aspiration prayer from the Tantra of the Great Perfection that Reveals the All-Penetrating Wisdom Mind of Samantabhadra.
Link for the aspiration prayer: https://www.lotsawahouse.org/tibetan-masters/rigdzin-godem/prayer-of-kuntuzangpo
During the time of Sakyamuni Buddha, Surya, the god of sun, took refuge in Buddha so as to save from Rahu. Buddha had to extend his size to overpower Rahu, for the latter was stubborn to comply the command. Rahu then fled for not being able to confront the magical strength of Buddha.
When Rahu hides the sun or moon, when earthquake happens, or during solstices or when year ends, we are advised to visualize Samantabhadra and recite aspiration prayer from the Tantra of the Great Perfection that Reveals the All-Penetrating Wisdom Mind of Samantabhadra.
Link for the aspiration prayer: https://www.lotsawahouse.org/tibetan-masters/rigdzin-godem/prayer-of-kuntuzangpo