Kala (कालः)

Kala (Samskrit : कालः) means "time period" in a broad sense. The concept of time is explained systematically in vedanga jyotisha (astronomy). It is significant that time has been considered both at the microcosmic and the macrocosmic levels. Various Puranas also describe Kalapramana that existed previously.

Kala is kshayakari (क्षयकारी । exhausting) or vriddi kari (वृध्दिकारी । flourishing). Firstly Kala, refers to the inexorable flow of both creation and unfolding of the universe and its subsequent destruction, in time cycles of huge dimensions. Secondly, Kala refers to the shorter and relative time periods on earth, the days and nights, paksha, masa (months), ayana (uttarayana and dakshinayana), samvatsara (year) and this leads to the bigger units of yugas which again refer back to the cycles of srishti (सृष्टिः । creation) and kshaya (क्षयः। decay) that the universe passes through.

Many of astronomers of ancient days had different versions of what time period constituted the yugas on the macroscopic scale of time.

कालः सृष्टिः च ॥ Kala and Creation

Kala as related to the Universe refers to the theories of creation, the cosmogenesis on the macroscopic scale.

Kala pertains to that cycle where creation begins with the intense effort, tapas and the determination, the samkalpa, of Brahman as given in the Prasnopanishad and reiterated by the Taittiropanishad

तस्मै स होवाच प्रजाकामो वै प्रजापतिः स तपोऽतप्यत स तपस्तप्त्वा स मिथुनमुत्पादयते । रयिं च प्रणं चेत्येतौ मे बहुधा प्रजाः करिष्यत इति ॥ ४ ॥ (Pras. Upan. 1.4)

सोऽकामयत । बहुभ्यां प्रजायेयेति । स तपोऽतप्यत । स तपस्तप्त्वा । इदँ सर्वमसृजत । (Taitt. Upan. 2.6)

Summary : Pippalada, the venerable seer, tells about the beginning of the creation that the creator became desirous of creating and with that in view, practiced tapas and created a pair Rayi, the moon, the food and Prana, fire, the consumer, the surya (corresponding to matter and life force) with the intention of springing forth all dual existence whatsoever from them. In a similar spirit Taittriyopanishad also tells us that the creator at the beginning practiced tapas and having done so created all that exists. Shri. Dharampal rightly explained the influence of Kala on the Chitta (manas) or the psyche of people of Bharatavarsha as follows

The universe once created passes through a number of cycles of growth and decay, and at the end is drawn back into Brahman. This cycle of creation of the universe from Brahman and its disappearance into Him is repeated again and again according to the predefined flow of time. Within this large cycle, there are a number of shorter cycles, at the end of each of which the universe gets destroyed, and created again at the beginning of the next. Thus the universe keeps on passing through repeated cycles of creation and destruction, and there are series of cycles within cycles.

The terms ‘creation’ and ‘destruction’ are probably not wholly appropriate in this context. Because, at the time of creation, it is not something external to Him that Brahman creates. He only manifests Himself in the varied forms of the universe, and at the end He merely contracts those manifestations into Himself, and thus there is in reality nothing that gets created or destroyed. The universe, in a sense, is a mere play of Brahman, a cosmic game of repeated expansion and contraction of the ultimate essence of the universe. But it is a game that is played according to well defined cycles of time. The universe is play, but the play is not arbitrary. Even Brahman is governed by kala. He manifests and contracts according to a definite flow of time that even He cannot transcend.

Every Indian is probably aware of this Indian view of the universe as the play of Brahman. Every Indian is also aware of the supremacy of kala in this play. Many Indians may not know the very detailed arithmetic of the various cycles of time that is given in the Puranas. But the thought that the universe is a play that had no beginning and will have no end, and that this play of Brahman proceeds according to the inexorable flow of kala, is deeply etched on the chitta of the people of India.

कालमानम् ॥ Kalamanam

Kalapramana or the duration of time and measurements, are variously described in different texts. The calculations are based on nakshatras, suryodaya, chandra (moon), planetary transits for earthly time measurements. Thus we have nakshatramana, sauramana, chandramana etc ways to measure time. Astronomy and Astrology texts such as Surya Siddhanta, deal extensively with the topic of time and its calculations ranging from less than a second to trillions of years. Kala is classified into two according to Surya Siddhanta as follows

लोकानामन्तकृत्कालः कालोन्यः कलनात्मकः । स द्विधा स्थूलसूक्ष्मत्वान्मू्र्त्तश्चामूर्त उच्यते॥ (Sury. Sidd. 1.10) (Page 5 of Book in Reference

Summary : Kala is (1) Anadi and Ananta (is continuous and endless) which destroys all animate and inanimate things (2) Kalanatmaka (that which can be known). The later kind of time which is measurable time is again of two kinds. (1) Sthula (2) Sukshma. Sthula time is that which can be measured hence called Murta, while Sukshma is (a small time scale) which cannot be measured (immeasurable due to its smallness) hence called Amurta.

First kind of Kala cannot be imagined as one cannot know its origin and end, it is indivisible and exists as is even though Brahmas and Indras pass, creation and destruction take place, hence Mrtyu is called also called Kala.

Various texts such as Manusmrti, Bhagavata Purana, Vishnu purana, Bhavishya purana and Mahabharata, also deal elaborately with the creation of the universe, of the division of the movement of the Universe into specified periods called the Yugas.

Yuga System

On the macroscopic scale of time, the yuga system is highly evolved in the Indian Astronomy. Many important elements of planets and other parameters are given in terms of the number of revolutions in the course of a long period of time called yuga. The concept of Yugas is extensively discussed in various puranas.

While in the Vedanga Jyotisha the word yuga was used to mean a period of 5 years, in later works the word meant a large period of time. Yugas of large periods of time have been used to indicate the rates of motion of planets and other important points of astronomical significance. This technique enabled them to express these constants as integers, though very large, thus avoiding very inconvenient fractions. Indian time scales are unique in that they account for the cyclic and linear aspects as seen from the astronomical texts.

Yuga in Vedas

Astronomical knowledge was necessary since early Rig vedic times for the day-today-life of the people seasons for sowing, rains for growth and reaping were all acquired. Direct connection of astronomy, particularly the lunar transits, are seen in the performance of monthly rites such as Darsapurnamasa and seasonal rites such as chaturmasya. Thus vedic people had knowledge required for their religious activities. The Vedic astronomers evolved a system of five years yuga. As seen in Rigveda time period of yuga was mentioned

दीर्घतमा मामतेयो जुजुर्वान् दशमे युगे । (Rig Veda 1.158.6)

The names of the five years of a yuga being

1. संवत्सरः॥ Samvatsara
2. परिवत्सरः ॥ Parivatsara
3. इडावत्सरः ॥ Idaavatsara
4. अनुवत्सरः ॥ Anuvatsara
5. इद्वत्सरः ॥ Idvatsara

Yuga (युगम्) is one of the four large periods into which the basic Chaturyuga cycle is divided, it forms the basic Indian cycle of creation and destruction. Yuga Pramana is calculated in terms of Human varshas and Divya varshas. Bhagavata Purana describes the concept of time and yugas (in Divya varshas) in the following verses

कृतं त्रेता द्वापरं च कलिश्चेति चतुर्युगम् । दिव्यैर्द्वादशभिर्वर्षैः सावधानं निरूपितम् ॥ १८ ॥ (Bhag. Pura. 3.11.18)

चत्वारि त्रीणि द्वे चैकं कृतादिषु यथाक्रमम् । सङ्ख्यातानि सहस्राणि द्विगुणानि शतानि च ॥ १९ ॥ (Bhag. Pura. 3.11.19)

Meaning : The four yugas are namely Krta, Treta, Dvapara and Kali consisting of 12,000 divya varshas, in the order of 4000, 3000, 2000, and 1000 divya years respectively. The earliest reference to a mahayuga's division into 4 yugas is found in the Aitereya Brahmana belonging to the Rig Veda.

कलिः शयानो भवति संजिहानस्तु द्वापरः। उत्तिष्ठंस्त्रेता भवति कृतं सम्पद्यते चरंश् चरैवेति चरैवेति... (Aite. Brah. 7.15)

Thus, the concept of four yugas is vedic in origin, although the exact measure is not mentioned we rely on the Puranas and other texts.

Srsthi in Puranas

Thus even though the concept of yugas is vedic in origin, Puranas have dealt with this subject extensively. One of the 5 lakshanas of Puranas include that such texts should contain the information of Creation and Manvantaras. Thus apart from description about the scheme and number of years, Puranas also deal with many other topics. However, the macrocosmic and microcosmic time scales are varying in Puranic texts. Commonly it is the सृष्टिप्रकरणम् Srsthiprakaranam that deals with the information regarding Kalapramanas. Below is a list of Puranas and the information of Kalapramana contained therein.

• Brahmanda Purana (Purvabhaga)
• Vishnu Purana (Prathama Amsha)
• Padma Purana (Khanda One)
• Vishnudharmottara Purana (Khanda 1 and 2)
• Kurma Purana (Purvabhaga)
• Linga Purana (Purvabhaga)
• Narada Purana (Purvardha)
• Matsya Purana (Adhyaya 3 and others)

चतुर्युगाः ॥ Chaturyugas in terms of Divya Varshas

This scheme of the Yuga Pramana includes calculations of Kala, the macroscopic time, in terms of Divya varshas. According to Surya Siddhanta,

one human year = one day of devatas 

360 human years = one year of devatas (Divya varsha)

So when the time lengths of Krtayuga, Tretayuga, Dvapara and Kali yugas in human years are divided by 360 we get the lengths of those yugas in Divya Varshas.

Krtayuga = 17,28,000 years or 1728000/360 = 4,800 Divya varshas

Tretayuga = 12,96,000 years or 12,96,000/360 = 3,600 Divya varshas

Dvaparayuga = 8,64,000 years or 8,64,000/360 = 2,400 Divya varshas

Kaliyuga = 4,32,000 years or 4,32,000/360 = 1,200 Divya varshas

1 Mahayuga = 43,20,000 Human years = 12,000 Divya varshas

चतुर्युगाः ॥ Chaturyugas in terms of Human Varshas

Chaturyugas in terms of Human Varshas

Yuga Pramana involving the use of human varshas or years is well supported by astonomical texts. According to the puranas and the astronomical texts one Chaturyuga consists of 43,20,000 solar years. Thousand Chaturyugas is termed a Mahayuga equalent to a Kalpa, which is the larger cycle of creation and destruction, and is seen as the day of Brahma. The four Yugas comprising the Chaturyuga are:

1. कृतयुगम् ॥ Krtayuga
2. त्रेतायुगम् ॥ Tretayuga
3. द्वापरयुगम् ॥ Dvaparayuga
4. कलियुगम् ॥ Kaliyuga

It may be noted that the time period in four yugas are in the ratio of 4:3:2:1. One Mahayuga is ten times a Kaliyuga in its duration. However, Aryabhata I, the ancient Indian mathematician, revised the duration of the four yugas in a mahayuga and made them of equal duration, viz., 10,80,000 instead of the traditional yuga scheme of 4:3:2:1.

कृतयुगम् ॥ Krta Yuga

Krta is the first Yuga of the Chaturyuga cycle. In this Yuga Dharma represented by the bull supporting the universe stands securely on all four legs. The four legs of Dharma are said to be Vidya (knowledge and purity), Dana (charity), tapas (penance) and satya (truth) in rough translation. With the increase of adharma, dharma became diminished by one leg each, in each of the other yugas.

धर्मश्चतुष्पान्मनुजान् कृते समनुवर्तते । स एवान्येष्वधर्मेण व्येति पादेन वर्धता ॥ २१ ॥ (Bhag. Pura. 3.11.29)

According to the calculations of the Puranas, the length of the Krtayuga is 17,28,000 years. But with the passage of time, the universe starts getting more and more complex. The innate order starts getting disturbed. Dharma starts getting weakened. And, towards the end of Krta, the creator has to take birth on earth in various forms to re-establish the dharma.

त्रेतायुगम् ॥ Treta Yuga

The second Yuga of the Chaturyuga cycle. In this Yuga the bull representing Dharma is said to stand on three feet.

द्वापरयुगम् ॥ Dvapara Yuga

The third of the four yugas of the Chaturyuga cycle. In this Yuga the bull representing dharma, that holds the earth, is left with only two feet. Dvapara in the current Chaturyuga begins with the ascendance of Srirama and ends with the ascendance of Srikrishna from the earth.

कलियुगम् ॥ Kali Yuga

The fourth and the last Yuga of a Chaturyuga cycle. The current Kaliyuga began with the ascendance of Srikrishna from the earth after the Mahabharata war more than 5,000 years ago. Indian astronomical texts fix the time and date of the onset of current Kaliyuga either at the midnight of February 17/18 or the sunrise of February 18 of 3102 BCE (Julian reckoning). Further the mean midnight is as at Ujjaiyini (23^o 11'N Latitude and 75^o 46'E Longitude) meridian passing through Lanka on the equator according to the ardharatrika (midnight) system.

कल्पम् ॥ Kalpa

Kalpa is the period of one thousand Chaturyugas or Mahayugas, forming a day of Brahma. Surya Siddhanta describes as follows

युगानां सप्ततिस्सैका मन्वन्तरमिहोच्यते । कृताब्दसङ्ख्या तस्यान्ते प्रोक्तो जलप्लवः ॥ (Sury. Sidd. 1.18)

ससन्धयस्ते मनवः कल्पे ज्ञेयाश्चतुर्दश । कृतप्रमाणः कल्पादौ संधिः पञ्चदश स्मृताः ॥ (Sury. Sidd. 1.19)

Summary : 71 Mahayugas (containing 306,720,000 solar years) constitute a Manvantara (ruled by a Manu). At the end of it, in the number of solar years (17,28,000 solar years) equal to that of the Krtayuga (called as Sandhi period) a Jalaplava or a universal deluge is said to happen. Fourteen such Manu periods along with the Sandhi periods and the fifteenth sandhi at the beginning, having the same number of years as the Krtayuga constitute a Kalpa. A Kalpa is thus divided into 14 Manvantaras (मन्वन्तराणि), and there is a Manu, the patriarch, of each of the 14 Manvantaras. The list of Manus who were the rulers in different Manvantaras is given variously in different Puranas. Bhagavata Purana mentions as follows

त्रिलोक्या युगसाहस्रं बहिराब्रह्मणो दिनम् । तावत्येव निशा तात यन्निमीलति विश्वसृक् ॥ २२ ॥ (Bhag. Pura. 3.11.22)

निशावसान आरब्धो लोककल्पोऽनुवर्तते । यावद्दिनं भगवतो मनून् भुञ्जंश्चतुर्दश ॥ २३ ॥ (Bhag. Pura. 3.11.23)

Summary : A day of Brahma consists of one thousand cycles of four yugas (when creation proceeds). The night is also of the same duration when Brahma withdraws from creation (and is said to be in sleep). At the end of the night (cyclic time) the creation of the world (Kalpa) starts and proceeds so long as it is Brahma's day which covers the time period of fourteen Manus.

1 Kalpa = 1 Day of Brahma

360 Days and 360 Nights of Brahma = 1 Brahma Year

According to Matsya purana, a few names of the Kalpas are given as follows

प्रथमं श्वेतकल्पस्तु द्वितीयो नीललोहितः। वामदेवस्तृतीयस्तु ततोराथन्तरोऽपरः ।। २९०.३

रौरवः पञ्चमः प्रोक्तः षष्ठो देव इति स्मृतः। सप्तमोऽथ बृहत्कल्पः कन्दर्पोऽष्टम उच्यते ।। २९०.४

सद्योऽथ नवमः प्रोक्तः ईशानो दशमः स्मृतः। तम एकादशः प्रोक्तः तथा सारस्वतः परः ।। २९०.५

त्रयोदश उदानस्तु गारुड़ोऽथ चतुर्दशः। कौर्मः पञ्चदशः प्रोक्तः पौर्णमास्यामजायत ।। २९०.६

षोड़शो नारसिंहस्तु समानस्तु ततोऽपरः। आग्नेयोऽष्टादशः प्रोक्तः सोमकल्पस्तथापरः ।। २९०.७

मानवो विंशतिः प्रोक्तस्तत् पुमानिति चापरः। वैकुण्ठश्चापरस्तद्वल्लक्ष्मीकल्पस्तथापरः ।। २९०.८

चतुर्विंशतिमः प्रोक्तः सावित्री कल्पसंज्ञकः। पञ्चविंशस्ततो घोरो वाराहस्तु ततोऽपरः ।। २९०.९

सप्तविंशोऽथ वैराजो गौरि कल्पस्तथापरः। माहेश्वरस्तु स प्रोक्त स्त्रिपुरो यत्र घातितः ।। २९०.१०

पितृकल्पस्तथान्ते तु या कुहूर्ब्रह्मणः परा। इत्येवं ब्रह्मणो मासः सर्वपातकनाशनः ।। २९०.११

1. Svetakalpa (श्वेतकल्पः)
2. Nilalohita (नीललोहितः)
3. Vamadeva (वामदेवः)
4. Rathantara (राथन्तरः)
5. Raurava (रौरवः)
6. Deva (देवः)
7. Brhatkalpa (बृहत्कल्पः)
8. Kandarpa (कन्दर्पः)
9. Sadya (सद्यः)
10. Ishana (ईशानः)
11. Tama (तमः)
12. Sarasvata (सारस्वतः)
13. Udana (उदानः)
14. Gaaruda (गारुड़ः)
15. Kaurma (कौर्मः)
16. Narasimha (नारसिंहः)
17. Samana (समानः)
18. Agneya (आग्नेयः)
19. Soma (सोमः)
20. Manava(मानवः)
21. Puman (पुमान्)
22. Vaikuntha (वैकुण्ठः)
23. Lakshmi (लक्ष्मी)
24. Savitri (सावित्री)
25. Ghora (घोरः)
26. Varaha (वाराहः)
27. Vairaja (वैराजः)
28. Gauri (गौरी)
29. Maheshvara (माहेश्वरः)
30. Pitrkalpa (पितृकल्पः)

Indian astronomical siddhantas assumed that at the commencement of the Kalpa all the planets including Ketu were in conjunction (at the same celestial longitude) at the first point of Mesha and the ascending node (Rahu) of the Moon was 180 degrees away (i.e., at the first point of Tula).

ब्राह्मायुः ॥ Brahma Ayuh

The largest Indian time cycle is that of 100 years of the life of Brahma. Like Indra is a position, Brahma is also a position of a creator.

एवंविधैरहोरात्रैः कालगत्योपलक्षितैः । अपक्षितमिवास्यापि परमायुर्वयःशतम् ॥ ३२ ॥

यदर्धमायुषस्तस्य परार्धमभिधीयते । पूर्वः परार्धोऽपक्रान्तो ह्यपरोऽद्य प्रवर्तते ॥ ३३ ॥

पूर्वस्यादौ परार्धस्य ब्राह्मो नाम महानभूत् । कल्पो यत्राभवद्‍ब्रह्मा शब्दब्रह्मेति यं विदुः ॥ ३४ ॥ (Bhag. Pura. 3.11.32-34)

Summary : In due course of Kala, with such types of days and nights as described above, even the Ayu (long span of life) of 100 years of Brahma comes to an end. Half of this Brahmayu is called Parardha (परार्धः). The first parardha of Brahma's life has passed, now the other half is running.

Purva parardha constitutes the first fifty years and Dvitiya parardha makes the later fifty years of Brahma's age. At the beginning of the purva parardha, there was great Kalpa called Brahma Kalpa when Brahma was born called as Sabda Brahma. The subsequent Kalpa was called Padma Kalpa, when Brahma is said to have sprouted from the navel of Hari in the form of world-like lotus.

Current Kala

Currently we are in the Vaivasvata Manvantara, the seventh Manvantara of the Svetavaraha Kalpa, which is at the beginning of the second Parardha, or the fifty-first year of the current 100 year cycle of Brahma.

अयं तु कथितः कल्पो द्वितीयस्यापि भारत । वाराह इति विख्यातो यत्रासीत् शूकरो हरिः ॥ ३६ ॥ (Bhag. Pura. 3.11.36)

Sumamary : The present Kalpa of the second Parardha is known as Varaha (pertaining to the boar) as Hari assumed the boar-form (शूकरः) in this Kalpa.

Present Kalpa = Svetavaraha Kalpa (51 year of the 100 years of Brahma Ayuh)

Present Manvantara = Vaivasvata Manvantara (seventh of the 14 Manvantaras)

Present Mahayuga = 28th (of the 71 Mahayugas)

Present Chaturyuga = Kaliyuga (4th of the Chaturyugas)

The later time points in Kali yuga are calculated in our calendars and Panchangas.

शकाः ॥ Sakas or Eras

A Saka (शकः) or "era" is an important aspect in preparing calendars which are used for civil purposes as well as official, religious, historical and chronological records and events. Among several different Indian eras in use, the most popular ones are the Kali (कलि), Vikrama Saka (विक्रमशकः), Salivahana saka (शालिवाहनशकः), Kollam. In any era adopted, the starting point is called epoch from which day the future periods of time, the day, months, years are counted. Such a reference day of an era were likely historical events such as the coronation of a famous king, the birth of a famous person, astronomical event of significance. In Indian astronomical texts, generally the Kali era is adopted, which is considered more advantageous compared to later eras for the simple reason that it covers the antiquity of our civilization adequately unlike the more later eras.

Many other eras have been in use, Saptarshi, Yudhisthira, Buddha nirvana, Mahavira nirvana, Bengali san, Lakshmanasena among others.

Microcosmic Time Scale

Just as the macrocosmic Yuga system is discussed extensively in various texts, the microcosmic time scale is also widely explained in different texts and different scholars have given different measures. A few systems are discussed here below.

Surya Siddhanta

प्राणादिः कथितो मूर्तः त्रुट्याद्योऽमूर्तसंज्ञकः । षड्भिःप्राणैः विनाडी स्यात्तत्षष्ट्या नाडिका स्मृता ॥

नाडी षष्ट्या तु नाक्षत्रमहोरात्रं प्रकीर्तितम् । तत्त्रिंशता भवेन्मासः सावनोऽर्कोदयैःस्मृतः ॥

ऐन्दवस्तिथिभिः तद्वत्सङ्क्रान्त्या सौर उच्यते । मासैर्द्वादशभिर्वर्ष दिव्यं तदह उच्यते ॥ (Sury. Sidd. 11 - 13)

Summary : The time called Murta begins with Prana and the time called Amurta begins with Truti. The time which contains six Pranas is called Pala and that which contains sixty Palas is called a Nadika (also called Nadi or ghatika). The time which contains sixty Ghatikas is called Naakshatra Ahoratra (Sidereal Day and Night). Thirty Naakshatra Ahoratras makes up a Naakshatra Masa. Thirty Savana days (day counted from Sunrise to sunset) make a Savana month.

Shiva Mahapurana

Shivapurana mentions that Kala is controlled by Sadashiva with time based on the divisions involving Kshana, Truti, Lava, Nimesha, Kashtha, Muhurta, Day, NIght, Paksha, Masa, season, Samvatsara, Yuga, Kalpa and Mahakalpa as given in the following slokas

क्षणं त्रुटिर्लवं चैव निमेषं काष्ठकालिकम् ।। ३८ ।।

मुहूर्तकं त्वहोरात्रं पक्षमासर्तुवत्सरम् ।। अब्दं युगं तथा कल्पं महाकल्पं तथैव च ।। ३९ ।।

एवं स हरते कालः परिपाट्या सदाशिवः ।। (Shiv. Pura. 5.25.38 - 40)

Bhagavata Purana describes the smallest particles as Paramanus, two of which make up an Anu. Three such anus make up the Trasarenu. It is the smallest particle which is visible. (Bhag. Pura. 3.11.5-8) Another measure of Kala as mentioned in the Prashastapada Bhashya (chap 5) is also tabularized. After the lapse of a hundred years of Brahma (1 year of Brahma has 360 days of Brahma or Kalpa) there comes the time for the final deliverance of the Brahma of the time.

Macro and Microcosmic Time Scales

Different versions of time scales are given in various texts ranging from Puranas to Siddhantas. A few examples have been compiled in the table below.

Kala in Macro and Microcosmic Scales

No	Shiva Purana	Bhagavata Purana	Vaiseshika Darshana	Vedanga Jyotisha	Surya Siddhanta
1	Kshana	3 Trasarenu = Truti	1 Nimesha = time taken for twinkling of eyes	5 Gurvaksharas (letters of double maatra) or 10 matras = 1 Kashta	Prana
2	Truti	100 Trutis = Vedha	5 Nimesha = 1 Kashtha	31 Kashtas = 1 Pada	6 Pranas = Pala
3	Lava	3 Vedhas = Lava	30 Kashthas = 1 Kalaa	4 Padas (124 Kashtas) = 1 Kalaa	60 Palas = Nadika or Nadi or Ghatika
4	Nimesha	3 Lavas = Nimesha	15 Kalaas = 1 Nadika	10 and 1/20 Kalaas = 1 Nadika	60 Ghatikas = Nakahsatra Ahoratra
5	Kashta	3 Nimeshas = Kshana	30 Kalas = 1 Muhurta	2 Nadikas = 1 Muhurtha	30 Nakshatra Ahoratras = Nakshatra Masa
6	Muhurta	5 Kshanas = Kashta	30 Muhurtas = 1 Ahoratra (day and night)	30 Muhurthas = 1 Day (i.e., the civil day)	30 Savana (terrestrial) = Savana Month
7	Ahoratram	15 Kashtas = Laghu	15 Ahoratras = 1 Paksha (fort-night)	366 Days = 12 Solar months or 6 Rtus, or 2 Ayanas, or 1 Solar year
8	Paksha	15 Laghus = Nadika or Ghatika	2 Pakshas = 1 Masa (Month)	5 Solar Years = 1 Yuga
9	Masa	2 Nadikas = Muhurta	2 Masas = 1 Rtu (Season)
10	Abda (year)	6 or 7 nadikas = Prahara/Yama	3 Rtus or 6 Masas = 1 Ayana (Uttarayana = 1 Day of Devatas, Dakshinayana = 1 Night of Devatas)
11		4 Yamas = Day and Night (Ahahoratri)	6 Rtus or 12 Masas = 1 Samvatsara (Earth Year)
12		15 Days = Paksha	360 Samvatsaras(Earth years) = 1 Divyavarsha (1 Year of Devatas)
13		2 Pakshas = 1 Masa	1200 Divyavarshas = The Four Yugas
14		2 Masas = Rtu	1000 Four yugas = 1 Day of Brahma
15		6 Masas = Ayana
16		2 Ayanas = Samvatsara

कालमापनयन्त्राणि ॥ Instruments to measure time

Ghati Yantra Creative Model

Again our ancients had different systems to measure time, distance, weights and numbers which are discussed under the heading Standards of Measurement (मापनमानदण्ड:). Although the earlier texts do not describe many instruments of keeping time (except instruments such as Aadhaka mentioned in Vedanga Jyotisha), in the later day many astronomers such as Aryabhata, Bhaskaracharya, Ganesha Daivajna used different instruments to measure time. Some of them include

Gola Yantra (Actual and Depictive images)

• गोलयन्त्रम् ॥ Spherical instrument
• तुर्ययन्त्रम् ॥ Quarter circle instrument
• चापयन्त्रम् ॥ Semicircular Disc instrument
• धनुर्यन्त्रम् ॥ Bow and arrow instrument
• चक्रयन्त्रम् ॥ Disc instrument
• शङ्कुयन्त्रम् ॥ Cone instrument
• नाडीवलययन्त्रम् ॥ Shadow instrument
• फ़लकयन्त्रम् ॥ Spherical instrument
• यष्टियन्त्रम् ॥ Stick instrument
• घटियन्त्रम् ॥ Timing vessal
• कर्तरीयन्त्रम् ॥ Scissor instrument
• शकटयन्त्रम् ॥ Two pivoted sticks
• जलत्नलिकायन्त्रम् ॥ Star positioning instrument
• पीठयन्त्रम् ॥ Peetha Yantra

Astrolabes were used to know the position of stars and also calculate time in more recent years. Siddhanta Shiromani by Bhaskaracharya II extensively describes the construction of yantras for various purposes. The construction of Gola (Sidd. Shir. Yant. 3 and 4) and Ghati Yantras are given in Siddhanta Shiromani in the following sloka as an example

घटदलरूपा घटिता घटिका ताम्री तले पृथुच्छिद्रा। द्युनिशनिमज्जनमित्या भक्तं द्युनिशं घटीमानम्॥ सि. शि. यन्त्र.८ (Sidd. Shir. Yant. 8)

कालस्य ईश्वररूपम् ॥ Kala's Ishvaraswarupa

Defining Kala, Bhagavata Purana (Skanda 3) describes the different qualities of time and the divinity associated with it. Time is that divine form which is the cause of change in appearance of things.

रूपभेदास्पदं दिव्यं काल इत्यभिधीयते । भूतानां महदादीनां यतो भिन्नदृशां भयम् ॥ ३७ ॥

योऽन्तः प्रविश्य भूतानि भूतैरत्त्यखिलाश्रयः । स विष्ण्वाख्योऽधियज्ञोऽसौ कालः कलयतां प्रभुः ॥ ३८ ॥

He pervades in all beings (भूतानि) and supports them. He is Vishnu, the deity of Yajnas, who blesses the performer with the fruits of Yajnas. He is the ruler of rulers.

न चास्य कश्चिद् दयितो न द्वेष्यो न च बान्धवः । आविशत्यप्रमत्तोऽसौ प्रमत्तं जनमन्तकृत् ॥ ३९ ॥

यद्‍भयाद् वाति वातोऽयं सूर्यस्तपति यद्‍भयात् । यद्‍भयाद् वर्षते देवो भगणो भाति यद्‍भयात् ॥ ४० ॥

He is neither shows compassion on anyone, nor hates, nor is a relative to anyone. He is always alert, and takes possession of the inattentive people to their destruction. It is out if fear of Kala that the wind blows, the sun shines, the devatas shower rains and the celestial bodies shine forth.

यद् वनस्पतयो भीता लताश्चौषधिभिः सह । स्वे स्वे कालेऽभिगृह्णन्ति पुष्पाणि च फलानि च ॥ ४१ ॥

स्रवन्ति सरितो भीता नोत्सर्पत्युदधिर्यतः । अग्निरिन्धे सगिरिभिः भूर्न मज्जति यद्‍भयात् ॥ ४२ ॥

सोऽनन्तोऽन्तकरः कालो अनादिरादिकृदव्ययः । जनं जनेन जनयन् मारयन् मृत्युनान्तकम् ॥ ४५ ॥

It is out of fear (rather obedience to or in alignment with) that the trees, creepers, medicinal herbs and plants blossom forth and bear fruits in accordance to the seasonal changes. It is Kala that controls the flow of rivers and keeps the checks of seas from overflowing (crossing fixed limits). It is this power that makes the fires burn and prevents the earth though burdened with the mountains from submerging in the seas.

It is due to the control of Kala that the sky gives space for the living breathing entities and Mahat pervades into the world enveloped in seven sheaths. It is this power which drives the devatas, who control the mobile and immobile beings, to carry out their duties of creation in every Yuga. Kala is Ananta (endless) but puts an end to all. TIme is Anadi (beginningless) but marks the beginning of all. Kala is Avyaya (immutable). Time causes beings to be born and by means of death takes them to their end.