Sunrise, sunset, and day duration are not just astronomical events but spiritual markers that guide daily life in Indian Vedic astrology. They align human activities with cosmic rhythms, ensuring harmony and balance. From scheduling rituals to understanding planetary influences, these timings form the foundation of astrological and spiritual practices in Hinduism.

Sunrise (सूर्योदय)

Sunrise is the moment when the upper edge of the Sun becomes visible on the horizon. It marks the beginning of the day in Vedic astrology and sets the tone for all astrological and spiritual activities.

Importance in Vedic Astrology

1. Start of the Day:- Panchang begins with sunrise. Tithi, Nakshatra, and planetary transits are calculated from sunrise.

2. Auspicious Activities:- Many auspicious rituals, such as pujas, havans, and fasts, are scheduled to start after sunrise.

3. Brahma Muhurta:- Brahma Muhurta starts exactly 2 Muhurta (1 Muhurta = 48 minutes approx.) before sunrise and ends 48 mins before it. So the time approximately 96 minutes before sunrise is considered Brahma Muhurta, ideal for meditation and spiritual practices.

Sunset (सूर्यास्त)

Sunset is the moment when the Sun's upper edge dips below the horizon. It signifies the end of the day and transitions into the night.

Importance in Vedic Astrology

1. Twilight (Sandhya):- The period around sunset is known as "Sandhya Kaal," a sacred time for prayers and evening rituals.

2. Choghadiya Muhurta:

   • Sunset divides the day and night for calculating auspicious Choghadiyas (hourly Muhurtas).

Day Duration (दिन की अवधि)

Day duration refers to the time from sunrise to sunset. It varies throughout the year due to the Earth’s tilt and orbit around the Sun.

Calculation of Day Duration

1. Equinox:- On equinox days, day and night are equal in duration.
2. Seasonal Variation:- In summer, days are longer due to the Sun's position in the Northern Hemisphere. In winter, days are shorter as the Sun is in the Southern Hemisphere.

Importance in Vedic Astrology

1. Determining Hora (Hours):- A day is divided into 24 Horas (planetary hours). Daytime and nighttime Horas are based on the length of day and night.

2. Auspicious Timings (Muhurta):- Specific durations, such as Rahu Kaal, Yama Gandam, and Gulika Kaal, are derived from the day's length.

3. Seasonal Impacts:- Longer days in summer signify stronger solar energy, beneficial for specific rituals and activities. Shorter days in winter align with introspective and spiritual practices.