Time and the calendar

Ancient Hindu astronomers calculated the length of the year using careful observation and mathematical models, reaching figures that were accurate to within a few minutes of today's measurements — all without telescopes.

Hindu cosmology sees time as vast beyond imagining and as moving in giant cycles of creation and dissolution that repeat without end. No single human lifetime, or even the whole of human history, is more than a tiny moment in it.

The Hindu calendar uses two different systems to set festival dates. Solar festivals fall on the same point in the sun's path each year. Lunar festivals follow the moon's cycle, so their date on the Western calendar shifts from year to year.

Yes, in a basic way. Much of Western thought sees time as a straight line with a clear start and end. Hindu cosmology sees time as a vast wheel, turning through cycles with no fixed beginning or final stop.

The four yugas are four great ages — Satya, Treta, Dvapara, and Kali — that together make up one enormous cycle of time. Hindu tradition sees the universe moving through these ages again and again, like a wheel turning.

A Sankranti is the moment the sun moves into a new zodiac sign. There are twelve each year, but Makar Sankranti, when the sun enters Capricorn, is the most widely celebrated because it marks a major turning point in the solar year.

A kalpa is one day in the life of Brahma, the creator. According to Hindu cosmology, it lasts 4.32 billion years. The universe is created at the start of a kalpa and dissolves at its end.

A Karana is half of a lunar day, called a tithi. There are 11 Karanas in total, and they are used in the Panchanga to help choose good times for rituals and important events.

A Manvantara is one great age of time ruled by a being called Manu. Hindu cosmology counts 14 Manus in every cosmic cycle, and we are living in the age of the seventh.

A tithi is a lunar day in the Hindu calendar. It marks a specific phase of the moon and is used to fix the timing of festivals, rituals, and personal observances.

A Yoga in the Panchanga is one of 27 time periods, each with its own quality of auspiciousness. It is calculated by adding the positions of the Sun and Moon in the sky.

Adhika Masa is an extra month added to the Hindu lunar calendar every few years to keep it in step with the solar year. It is also called Purushottama Masa or Mala Masa, and the tradition gives it a special spiritual character.

Amavasya is the new moon day in the Hindu calendar. It is seen as the most powerful time to honour ancestors through offerings and prayer, because the tradition holds that the ancestors are especially close and reachable on this day.

A muhurta is a favorable window of time chosen for important events like weddings, starting a business, or a child's first day of school. It comes from the Hindu calendar and is treated as a belief and a long-standing custom.

Brahma Muhurta is a period roughly one and a half hours before sunrise. The tradition sees it as the best time of day for meditation, prayer, and study.

Kali Yuga is the last and darkest of the four great ages in Hindu cosmology. According to tradition, it began at the moment of Krishna's death, a point placed in the distant past.

Kshaya Masa is a lunar month that is considered lost or deleted in the Hindu calendar. It is extremely rare, happening roughly once every 141 years.

Nitya Pralaya is the idea in Hindu cosmology that every night, when all beings fall into deep sleep, a tiny version of cosmic dissolution happens. It links the rhythm of sleep to the great cycles of creation and destruction.

Pitru Paksha is a sixteen-day period in the Hindu lunar calendar set aside for honouring ancestors. It falls in the dark fortnight of the month of Ashwin and ends on the new moon day called Mahalaya Amavasya.

Rahu Kalam is a period each day believed to be ruled by Rahu, a shadow planet seen as inauspicious. Many people, especially in South India, avoid starting important activities during this time.

Chaturmas is a four-month period each year when many Hindus pause auspicious ceremonies and observe certain restrictions. It is tied to the belief that Lord Vishnu rests in a deep sleep during this time.

Pralaya means the dissolution or ending of the universe. Hindu cosmology describes several kinds of Pralaya, from small daily cycles to the complete end of all existence.

Hindus use two main types of calendar. The solar calendar tracks the sun's movement through the sky. The lunar calendar tracks the moon's phases. Different regions of India follow different ones, which is why the same festival can fall on different dates depending on where you are.

The Drik vs. Vakya debate is about which method to use when calculating the Hindu calendar. One method uses ancient fixed formulas passed down through the centuries. The other uses modern astronomy. Both are in use today, and they sometimes give different dates for the same festival.

The Hindu calendar is a lunisolar system used to track time, set festivals, and find auspicious days. Several regional versions exist across India and the diaspora.

The Jovian cycle is a system of 60 named years based on the planet Jupiter's movement through the sky. It is used in Hindu calendars, especially in South India, to track time and mark life events.

Kalachakra means the Wheel of Time. In Hindu thought, time is not just a measurement but a living force that creates, sustains, and destroys everything in the universe.

A Panchanga is a traditional Hindu almanac. The word means 'five limbs', and it tracks five things: the lunar day, the weekday, the lunar mansion, a special calculation called yoga, and a half-day unit called karana.

The Saptarishi calendar is an ancient Hindu way of counting years by tracking the seven sage-stars through the sky. It runs in a long cycle of 2700 years and is still used in some parts of India today.

Ekadashi is the eleventh day of each lunar fortnight and is one of the most widely observed fasting days in the Hindu calendar. It is closely tied to the worship of Vishnu and is seen as a day of special spiritual power.

Purnima, the full moon day, is one of the most sacred days in the Hindu calendar. It marks a peak of lunar energy and is tied to fasting, worship, charity, and some of the biggest festivals in the year.

The Nakshatra system divides the sky into 27 (or sometimes 28) lunar mansions. It is one of the oldest parts of the Hindu calendar and shapes everything from naming children to choosing the right day for a ritual.

The Vikrama Samvat and the Saka era are two different Hindu calendar systems, both still in use today. They start from different points in history, mark their new year on different days, and are used in different parts of India.

Each yuga has a dawn period called Sandhya and a twilight period called Sandhyamsha. These transition periods are added to the core length of each yuga and make up one-tenth of it on each side.

Uttarayana and Dakshinayana are the two halves of the Hindu solar year. The sun's northward journey is seen as auspicious and spiritually bright, while the southward journey is quieter and more inward. Together they shape the ritual calendar in important ways.

There is no single Hindu new year. Different regions of India and the Hindu diaspora mark the new year on different days, each tied to their own calendar, harvest season, and local tradition.