In Indian astronomy, yoga (also called nityayoga) is a period of time, of varying lengths, during which the sum of the nirayana longitudes of the Sun and the Moon increases by an amount of 13 degrees 20 minutes (or, equivalently, 800 minutes). [1] While considering the sum, when the sum is 360 degrees or more, then 360 degrees is subtracted from the sum to make the sum an angle between 0 degree and 360 minutes. Consider a moment T1 when the sum of the longitudes of the Sun and the Moon is 0 degree and let T2 be the next immediate moment when the sum of the longitudes of the Sun and the Moon is 13 degree 20 minutes. The duration of time between the moments T1 and T2 is the first yoga. Similarly, let the next immediate moment when the sum of the longitudes of the Sun and Moon is 26 degrees 40 minutes. The duration of time between the moments T2 and T3 is the second yoga. The third, fourth and higher yoga-s are defined in a similar way. Since 27 X 13 degrees 20 minutes = 360 degrees, at the end-moment of the 27th yoga, the sum of the nirayana longitudes of the Sun and Moon would be 0 degree. The numbering of the yoga-s then starts afresh from that point. It appears that the astronomical yoga-s are in no way related to any astronomical phenomena. [2] S. B. Dikshit in his Bhāratīya Jyotiṣ Śāstra observes: "It is not known what planetary position in the sky is indicated by yoga, and it is useful only in astrology." [3]
In Indian astrology, the term yoga has been used to indicate luni-solar distances and planetary situations, associations, and combinations. When one planet or house is related to another by placement, aspect or conjunction in a particular way then it is said that the planets and houses are in a particular yoga.
In the traditional Indian calendars or almanacs, that is in Pañcāṅg-s, Yoga or Nityayoga is one of the five elements or organs or limbs that constitute the Pañcāṅg-s, the "five organs" in the literary meaning of the term Pañcāṅg. The other four elements are Nakṣatra , Tithi , Vāra and Karaṇa.
The names of the 27 nitayoga are:
Nityayoga or yoga has a prominent place in traditional Indian almanac known as Pañcāṅg. It is one of the five elements that constitutes the pañcāṅg-s, that is, the five elements that define a Pañcāṅg. However, the yoga-s entered the Pañcāṅg calculations only several centuries after the other four elements became parts of the Indian alamanac. Pancha-siddhantika , a text on astronomy composed around 505 CE by Varāhamihira gives the methods of calculating nakṣatra-s and tithi-s but does not give any method for calculating yoga-s. Similarly, Bṛhat Saṃhitā , a work on astrology also by Varāhamihira has long discussions on the effects of nakṣatra-s but is silent on the effects of yoga-s. These facts indicate that the concept of yoga-s did not exist at the time of Varāhamihira. The currently available Brāhmasphuṭasiddhānta composed by Brahmagupta in c.628 CE has just one verse containing a reference to yoga, but all internal evidences point to the possibility of the verse being a much later interpolation. Khaṇḍakhādyaka , another treatise composed by Brahmagupta in c.665 CE has a couplet of verses referring to yoga. These verses have also been determined as later interpolations. All these point to the fact that the concept of yoga in astronomy arose post Brahmagupta. Lalla (c. 720–790 CE) in his Śiṣyadhīvṛddhidatantra mentions the yoga-s in detail. Surya Siddhanta , the founding text of the Saura-pakṣa in Indian astronomy, of undetermined authorship believed to have been composed in the 4th-5th century CE but again believed to have undergone a substantial revision in around 800 CE presents the list of all the 27 yoga-s as they are used in modern Pañcāṅg-s and also methods of calculating the yoga-s. All these evidences suggest that the concept of yoga arose sometime around 700 CE and became an integral part of the Pañcāṅg-s only after around 700 CE. [3]
The word vyātīpāta occurs in two verses in Brāhmasphuṭasiddhānta, but from the context of the occurrence of the word, it is clear that it is not referring to the vyātīpāta that occurs as the 17th yoga in the list of 27 yoga-s. It is referring to one of two mahāpāta-s which occur when the Sun and the Moon are in parallel declination and this happens when the sum of the longitudes of the Sun and Moon is 180°. There are two moments in every lunar month when this happens. One of them is called the vyātīpāta and other vaidhṛti. In order to find these mahāpāta-s one has find the sum of the longitudes of the Sun and the Moon. This must have led to the idea of finding yoga-s by finding the sum of longitudes just as tithi is determined by the difference of longitudes. [3]
There is another theory regarding the origin of the yoga concept in Indian astronomy. According this view, the astronomical yoga came into being in attempts to predict the phenomena of eclipses. [4]
Robert Sewell's The Indian Calendar contains a section which explains in meticulous detail how the Yoga at sunrise on a day specified by a date in the Common Era can be determined. The procedure also explains how to find how much time has elapsed at the moment of sunrise since the beginning of the Yoga. [5]
The lengths of the various yoga-s varies from yoga to yoga. The following table gives the mean length, the greatest length and the least length of the yoga-s. [6] It follows that the total length of a yoga-cycle consisting of 27 yoga-s is 26 days 10 hours 12 minutes 47 seconds.
Hours | Minutes | Seconds | |
---|---|---|---|
Mean | 22 | 35 | 44.7 |
Greatest | 24 | 36 | 24 |
Least | 20 | 52 | 58 |
There is a different system of yoga-s in use in India. This system consists of 28 yoga-s, in contrast to 27 yoga-s in the system already explained, and the names and the rules for the determination of these yoga-s are different from the ones given earlier. In this system, the succession of the yoga-s depends the day of the week. Hence it has absolutely no connection whatsoever with any astronomical phenomena as the week has no definable relation to the motion of the moon or the sun. This system of yoga-s do not find any mention in Sūrya-sddhānta . In some Hindu calendars yoga-s of this system are also given for each day of the month. But these yogas are only of astrological interest.
The names as well as the rules for the determination of the 28 yoga-s as given in Śrīpati's Jyotiṡa Ratnamāla are given below. [7] [8]
The rule assumes a cycle of 28 nakṣatra -s which includes the 28th nakṣatra, namely, Abhijit. The 28 yoga-s are assigned as follows: [7]
Hindu astrology, also called Indian astrology, Jyotisha and, more recently, Vedic astrology, is the traditional Hindu system of astrology. It is one of the six auxiliary disciplines in Hinduism that is connected with the study of the Vedas.
The Hindu calendar, also called Panchanga, is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka found in the Deccan region of Southern India and the Vikram Samvat (Bikrami) found in Nepal and the North and Central regions of India – both of which emphasize the lunar cycle. Their new year starts in spring. In regions such as Tamil Nadu and Kerala, the solar cycle is emphasized and this is called the Tamil calendar and Malayalam calendar and these have origins in the second half of the 1st millennium CE. A Hindu calendar is sometimes referred to as Panchangam (पञ्चाङ्गम्), which is also known as Panjika in Eastern India.
In Vedic timekeeping, a tithi is a "duration of two faces of moon that is observed from earth", known as milа̄lyа̄ in Nepal Bhasa, or the time it takes for the longitudinal angle between the Moon and the Sun to increase by 12°. In other words, a tithi is a time duration between the consecutive epochs that correspond to when the longitudinal angle between the Sun and the Moon is an integer multiple of 12°. Tithis begin at varying times of day and vary in duration approximately from 19 to 26 hours. Every day of a lunar month is called tithi.
Aryabhata or Aryabhata I was the first of the major mathematician-astronomers from the classical age of Indian mathematics and Indian astronomy. His works include the Āryabhaṭīya and the Arya-siddhanta.
Brahmagupta was an Indian mathematician and astronomer. He is the author of two early works on mathematics and astronomy: the Brāhmasphuṭasiddhānta, a theoretical treatise, and the Khandakhadyaka, a more practical text.
A panchāngam is a Hindu calendar and almanac, which follows traditional units of Hindu timekeeping, and presents important dates and their calculations in a tabulated form. It is sometimes spelled Panchāngamu, Pancanga, Panchanga, Panchaanga, or Panchānga, and is often pronounced Panchāng. Panchangas are used in Jyotisha.
Varāhamihira, also called Varāha or Mihira, was a Hindu astrologer-astronomer who lived in or around Ujjain in present-day Madhya Pradesh, India.
Nakshatra is the term for Lunar mansion in Hindu astrology and Buddhist astrology. A nakshatra is one of 27 sectors along the ecliptic. Their names are related to a prominent star or asterisms in or near the respective sectors. In essence, a nakshatra simply is a constellation. Every nakshatra is divided into four padas.
The Tibetan calendar, or the Phukpa calendar, known as the Tibetan lunar calendar, is a lunisolar calendar composed of either 12 or 13 lunar months, each beginning and ending with a new moon. A thirteenth month is added every two or three years, so that an average Tibetan year is equal to the solar year. The 15th century Phukpa calendar is the main Tibetan calendar, and the Karma Kagyu's Tsurluk calendar is also in current use. The Tibetan New Year celebration is Losar, which falls either in the months of February or March in the Gregorian calendar.
Utpala, also known as Bhaṭṭotpala was an astronomer from Kashmir region of present-day India, who lived in the 9th or the 10th century. He wrote several Sanskrit-language texts on astrology and astronomy, the best-known being his commentaries on the works of the 6th-century astrologer-astronomer Varāhamihira.
Indian astronomy refers to astronomy practiced in the Indian subcontinent. It has a long history stretching from pre-historic to modern times. Some of the earliest roots of Indian astronomy can be dated to the period of Indus Valley civilisation or earlier. Astronomy later developed as a discipline of Vedanga, or one of the "auxiliary disciplines" associated with the study of the Vedas dating 1500 BCE or older. The oldest known text is the Vedanga Jyotisha, dated to 1400–1200 BCE.
Vedanga Jyotisha, or Jyotishavedanga, is one of earliest known Indian texts on astrology (Jyotisha). The extant text is dated to the final centuries BCE, but it may be based on a tradition reaching back to about 700-600 BCE.
Tantrasamgraha, or Tantrasangraha, is an important astronomical treatise written by Nilakantha Somayaji, an astronomer/mathematician belonging to the Kerala school of astronomy and mathematics. The treatise was completed in 1501 CE. It consists of 432 verses in Sanskrit divided into eight chapters. Tantrasamgraha had spawned a few commentaries: Tantrasamgraha-vyakhya of anonymous authorship and Yuktibhāṣā authored by Jyeshtadeva in about 1550 CE. Tantrasangraha, together with its commentaries, bring forth the depths of the mathematical accomplishments the Kerala school of astronomy and mathematics, in particular the achievements of the remarkable mathematician of the school Sangamagrama Madhava. In his Tantrasangraha, Nilakantha revised Aryabhata's model for the planets Mercury and Venus. According to George G Joseph his equation of the centre for these planets remained the most accurate until the time of Johannes Kepler in the 17th century.
Gaurabda is the name of the moon calendar used by Gaudiya Vaishnavism as part of the liturgy.
Budha is the Sanskrit word for the planet Mercury, personified as a god.
The Hindu calendar is based on a geocentric model of the Solar System. A geocentric model describes the Solar System as seen by an observer on the surface of the Earth.
Makarandasāriṇi is a Sanskrit astronomical table text composed by the Indian astronomer-mathematician Makaranda (c.1438-1478) hailing from Varanasi. In the Sanskrit astronomical literature such table texts are referred to as sāriṇi-s or koṣṭhaka-s. It is one of the most popular such texts ever composed in Sanskrit.
In Indian astronomy, a karaṇa is a half of a tithi. It is the duration of time in which the difference of the longitudes of the Sun and the Moon is increased by 6 degrees. A lunar month has 30 tithi-s and so the number of karaṇa-s in a lunar month is 60. These sixty karaṇa-s are not individually named. Instead, the originators of the concept have chosen 11 names to be associated with the karaṇa-s which means several karaṇa-s will be associated with the same name. Of these 11 names, four are fixed or immovables in the sense that they are associated with four unique karaṇa-s in a lunar month. These constant names are Śakuni, Catuṣpāda, Nāga and Kimstughna. The remaining seven names are variable or movable in the sense that there are several karaṇa-s associated with each of them. These names are Bava, Bālava, Kaulava, Taitila, Gara, Vaṇij and Vṛṣṭi.
In Indian calendrical systems, vāra denotes the week-day. It is one of the five elements that constitute the traditional almanacs called Pañcāṅga-s the other four being Nakshatra, Tithi, Karaṇa and Nityayoga. The concept of week, the unit of time consisting of seven days, is indigenous to Indian civilisation. The concept was probably borrowed by Babylonians and its use predates the use of the twelve zodiacal signs in Indian civilazation. The concept finds mention in Atharva Veda. The seven week-days are named after the seven classical planets as in the ancient Greek and Roman traditions.
In Indian astronomy and astrology, vyatipāta and vaidhṛti are two moments in the regular motion of the sun and the moon in the zodiac characterized by their certain special relative positions. These terms are also used to denote two of the 27 Nityayoga-s: vyatipāta is the 17th nityayoga and vaidhṛti is the 27th nityayoga.