Garudapurana 1.43.7

1.43.7

dvādaśyāṃ viṣṇave kāryaṃ śukle kṛṣṇe 'tha vā hara /
vyatīpāte 'yane caiva candarasūryagrahe śiva //

For Viṣṇu it should be performed on the twelfth day, either bright or dark, O Hara; / also at a vyatīpāta, at a solstice, and at an eclipse of the moon or the sun, O Śiva;