Sandhya (literally "junction" or "union") refers to the sacred transitional periods at dawn (Pratah Sandhya) and dusk (Sayam Sandhya), and sometimes noon (Madhyahna Sandhya). These are considered spiritually charged times when the veil between the physical and spiritual worlds is thinnest. Sandhya Vandana is the Vedic prayer ritual performed during these times, involving Achamana (purification), Pranayama, Gayatri Mantra chanting, and meditation. The practice is especially important for those who have undergone Upanayana (sacred thread ceremony). The Manusmriti states that performing Sandhya Vandana at both junctions is essential for maintaining spiritual purity. The evening Sandhya coincides with Godhuli Muhurat, considered auspicious for weddings and temple visits.