yadā meṣa-tulayor vartate tadāho-rātrāṇi samānāni bhavanti yadā vṛṣabhādiṣu pañcasu ca rāśiṣu carati tadāhāny eva vardhante hrasati ca māsi māsy ekaikā ghaṭikā rātriṣu.
yadā—when; meṣa-tulayoḥ—in Meṣa (Aries) and Tulā (Libra); vartate—the sun exists; tadā—at that time; ahaḥ-rātrāṇi—the days and nights; samānāni—equal in duration; bhavanti—are; yadā—when; vṛṣabha-ādiṣu—headed by Vṛṣabha (Taurus) and Mithuna (Gemini); pañcasu—in the five; ca—also; rāśiṣu—signs; carati—moves; tadā—at that time; ahāni—the days; eva—certainly; vardhante—increase; hrasati—is diminished; ca—and; māsi māsi—in every month; eka-ekā—one; ghaṭikā—half hour; rātriṣu—in the nights.
When the sun passes through Meṣa [Aries] and Tulā [Libra], the durations of day and night are equal. When it passes through the five signs headed by Vṛṣabha [Taurus], the duration of the days increases [until Cancer], and then it gradually decreases by half an hour each month, until day and night again become equal [in Libra].
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