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== परिचयः ॥ Introduction ==

== परिचयः ॥ Introduction ==

Vedanga Jyotisha is the earliest work dealing exclusively with astronomy. Available in two recensions, viz. the Ṛgvedic recension (called Archa Jyotisha) and the Yajurvedic recension (called Yajusha Jyotisha)<ref name=":2">K. S. Shukla, [https://www.insa.nic.in/writereaddata/UpLoadedFiles/IJHS/Vol04_1And2_11_KSShukla.pdf Astronomy in ancient and medieval India], Indian Journal of History of Science, Vol.4, Nos. 1-2 (1969), pp.99-106.</ref><ref name=":1">Kolachana, Aditya & Mahesh, Kaluva & Ramasubramanian, K.. (2019). Main characteristics and achievements of ancient Indian astronomy in historical perspective. 10.1007/978-981-13-7326-8_24. </ref>, they give an account of days and day-divisions, months, years, nakshatras, new moons and full moons, solstices seasons occurring in the cycle of five solar years and lay down rules for determining the beginning of a season, the length of a day, etc.<ref name=":2" />

People of the vedic times engaged seriously in the performance of yajnas at specific times prescribed by the shastras. Thus, it was necessary to have accurate knowledge of the science of time so that the times prescribed for performing the various vedic yajnas could be correctly predicted well in advance. Thus, it was essential to study the natural divisions of time caused by the motion of the Sun and Moon, such as days, months, seasons, and years, with special attention to the study of the times of occurrence of new moons, full moons, equinoxes, and solstices that is included under the purview of the science of Astronomy. Therefore, Astronomy in the vedic times, was essentially the science of time-determination that was motivated by the need to fix time for the various yajnas that were performed at different times in different seasons.<ref name=":1">Kolachana, Aditya & Mahesh, Kaluva & Ramasubramanian, K.. (2019). Main characteristics and achievements of ancient Indian astronomy in historical perspective. 10.1007/978-981-13-7326-8_24. </ref>

This work defines jyotisha (astronomy) as the science of time-determination and deals with months, years, muhurtas, rising nakshatras, new moons, full moons, days, seasons, and solstices. It states rules to determine the nakṣatra occupied by the Sun or Moon, the time of the Sun’s or Moon’s entry into a nakṣatra, the duration of the Sun’s or Moon’s stay in a nakṣatra, the number of new moons or full moons that occurred since the beginning of the yuga, the position of the Sun or Moon at the end of a new moon or full moon day or tithi, and similar other things. It gives also the measure of the water-clock, which was used to measure time, and tells when an intercalary month was to be added or a tithi was to be omitted. In short, it gives all necessary information needed by the vedic priest to predict times for the vedic sacrifices and other religious observances.<ref name=":1" />

In fact, this is the definition of astronomy given in Vedanga Jyotisha, the earliest available work dealing exclusively with astronomy that gives all necessary information needed by the vedic hota to predict times for the vedic yajnas and other observances.<ref name=":1" /><ref name=":2">K. S. Shukla, [https://www.insa.nic.in/writereaddata/UpLoadedFiles/IJHS/Vol04_1And2_11_KSShukla.pdf Astronomy in ancient and medieval India], Indian Journal of History of Science, Vol.4, Nos. 1-2 (1969), pp.99-106.</ref>

Ancient Indian astronomy may be classified into two main categories:

However, the Vedic literature also has references to astronomical events and observations. For eg. The Kaushitaki brahmana states that the year ended with the full moon at the Purva Phalguni.<ref name=":2" /> <blockquote>मुखम् वा एतत् संवत्सरस्य यत् फाल्गुनी पौर्णमासी । मुखम् उत्तरे फल्गू । पुच्छम् पूर्वे । तद् यथा प्रवृत्तस्य अन्तौ समेतौ स्याताम् । एवम् एव एतौ संवत्सरस्य अन्तौ समेतौ ।5.1<ref>Kaushitaki brahmana, [https://sa.wikisource.org/wiki/%E0%A4%95%E0%A5%8C%E0%A4%B7%E0%A5%80%E0%A4%A4%E0%A4%95%E0%A4%BF%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A6%E0%A5%AB Adhyaya 5].</ref></blockquote><blockquote>''mukham vā etat saṁvatsarasya yat phālgunī paurṇamāsī । mukham uttare phalgū । puccham pūrve । tad yathā pravr̥ttasya antau sametau syātām । evam eva etau saṁvatsarasya antau sametau ।5.1''</blockquote>Thus, ancient Indian astronomy may be classified into two main categories:

 

The day, in vedic literature was called Vasara (वासरः) or ahan (अहन्). And was reckoned from sunrise to sunrise. The variability of its length was known. For, the Ṛgveda invoking Somaraja says: <blockquote>''“O Somaraja, prolong thou our lives just as the Sun increases the length of the days.”<ref name=":1" />''</blockquote><blockquote>सोम राजन्प्र ण आयूंषि तारीरहानीव सूर्यो वासराणि ॥७॥<ref>Rgveda, Mandala 8, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AE.%E0%A5%AA%E0%A5%AE Sukta 48].</ref></blockquote><blockquote>''soma rājanpra ṇa āyūṁṣi tārīrahānīva sūryo vāsarāṇi ॥7॥''</blockquote>

 

The vedic astronomy is the astronomy of the vedic period, i.e., the astronomy found in the vedic saṃhitās and brāhmaṇas and allied literature. The principal avocation of the people in the vedic times being the performance of the vedic sacrifices at the times prescribed by the śāstras, it was necessary to have accurate knowledge of the science of time so that the times prescribed for performing the various vedic sacrifices could be correctly predicted well in advance. Astronomy in those times, therefore, was essentially the science of time-determination. It centred round the Sun and Moon and its aim was to study the natural divisions of time caused by the motion of the Sun and Moon, such as days, months, seasons, and years, special attention being paid to the study of the times of occurrence of new moons, full moons, equinoxes, and solstices.<ref name=":1" />

 

 

 

It is also stated there that the year ended with the full moon at the Pūrva-Phālgunī,3 (3Ibid, v. 1.) and that the spring commenced one day after the new moon of Caitra.4  (4Ibid, xix. 3.)

=== Divisions of a Day ===

 

The duration of daylight, reckoned from sunrise to sunset, was variously divided:

# Two parts called Purvahna (forenoon) and Aparahna (afternoon)

 

# Three parts called Purvahna, Madhyahna, and Aparahna.

There is one more work on jyotisha belonging to the later vedic period. It is known as Atharva-jyautiṣa. This work describes the muhurtas, tithis, karaṇas, nakshatras, and week days, and prescribes the deeds that should be performed in them. The names of the lords of the week days stated in this work viz. Āditya (Sun), Soma (Moon), Bhauma (the son of Earth), Bṛhaspati, Bhārgava (the son of Bhṛgu), and Śanaiścara (the slow-moving planet), are undoubtedly of Indian origin and must have been in use in India from very early times.6<ref name=":1" />

# Four parts called Purvahna, Madhyahna, Aparahna and Sayahna

 

# Five parts called Pratah, Sangava, Madhyahna, Aparahna, and Sayahna

== Day in Vedic Astronomy ==

The names of these five parts occur together in the Shatapatha brahmana,<blockquote>आदित्यस्त्वेव सर्व ऋतवः । यदैवोदेत्यथ वसन्तो यदा संगवोऽथ ग्रीष्मो यदा मध्यन्दिनोऽथ वर्षा यदापराह्णोऽथ शरद्यदैवास्तमेत्यथ हेमन्तस्तस्मादु मध्यंन्दिन एवादधीत तर्हि ह्येषोऽस्य लोकस्य नेदिष्ठं भवति तन्नेदिष्ठादेवैनमेतन्मध्यान्निर्मिमीते - २.२.३.९<ref>Shatapatha brahmana, Kanda 2, Adhyaya 2, [https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A4%A4%E0%A4%AA%E0%A4%A5%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A8/%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3_%E0%A5%A9 Brahmana 3].</ref></blockquote><blockquote>''ādityastveva sarva r̥tavaḥ । yadaivodetyatha vasanto yadā saṁgavo'tha grīṣmo yadā madhyandino'tha varṣā yadāparāhṇo'tha śaradyadaivāstametyatha hemantastasmādu madhyaṁndina evādadhīta tarhi hyeṣo'sya lokasya nediṣṭhaṁ bhavati tannediṣṭhādevainametanmadhyānnirmimīte''</blockquote>Of these names the first three occur in Ṛgveda, 5. 76. 3; <blockquote>उता यातं संगवे प्रातरह्नो मध्यंदिन उदिता सूर्यस्य । दिवा नक्तमवसा शंतमेन नेदानीं पीतिरश्विना ततान ॥३॥<ref>Rgveda, Mandala 5, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AB.%E0%A5%AD%E0%A5%AC Sukta 76].</ref></blockquote>and sāyam (evening) occurs in Ṛgveda, 8. 2. 20;  <blockquote>मो ष्वद्य दुर्हणावान्सायं करदारे अस्मत् । अश्रीर इव जामाता ॥२०॥<ref>Rgveda, Mandala 8, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AE.%E0%A5%A8 Sukta 2].</ref></blockquote>10. 146. 3, 40.<blockquote>उत गाव इवादन्त्युत वेश्मेव दृश्यते । उतो अरण्यानिः सायं शकटीरिव सर्जति ॥३॥<ref>Rgveda, Mandala 10, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%A7%E0%A5%A6.%E0%A5%A7%E0%A5%AA%E0%A5%AC Sukta 146].</ref></blockquote>Kauṭilya (Arthaśāstra, 1.19), Dakṣa, and Kātyāyana divided the day and night each into eight parts.<blockquote>नालिकाभिरहरष्टधा रात्रिं च विभजेत् । छाया-प्रमाणेन वा ।। ०१.१९.०६ ।।<ref>Arthashastra, Adhikarana 1, [https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A7/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A7%E0%A5%AF Adhyaya 19].</ref></blockquote>The days and nights were also divided into 15 parts each, and these parts were called muhūrta. The muhurtas falling during the days of the light and dark fortnights as well as those falling during the nights of the light and dark fortnights were given specific names (Taittirīya-brāhmaṇa, 3. 10. 1. 1–3). The fifteen days and nights of the light fortnight as well as the fifteen days and nights of the dark fortnight were also assigned special names (Taittirīya-brāhmaṇa, 3. 10. 1. 1–3; 3. 10. 10. 2).<ref name=":0">Taittiriya brahmana, Kanda 3, [https://sa.wikisource.org/wiki/%E0%A4%A4%E0%A5%88%E0%A4%A4%E0%A5%8D%E0%A4%A4%E0%A4%BF%E0%A4%B0%E0%A5%80%E0%A4%AF%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D_(%E0%A4%B5%E0%A4%BF%E0%A4%B8%E0%A5%8D%E0%A4%B5%E0%A4%B0%E0%A4%AA%E0%A4%BE%E0%A4%A0%E0%A4%83)/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%83_%E0%A5%A9/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%AA%E0%A4%BE%E0%A4%A0%E0%A4%95%E0%A4%83_%E0%A5%A7%E0%A5%A6 Prapathaka 10].</ref>

The day, called vāsara or ahan in the vedic literature, was reckoned from sunrise to sunrise. The variability of its length was known. The Ṛgveda (8. 48. 7) invoking Somarāja says: “O Somarāja, prolong thou our lives just as the Sun increases the length of the days.”<ref name=":1" /><blockquote>सोम राजन्प्र ण आयूंषि तारीरहानीव सूर्यो वासराणि ॥७॥<ref>Rgveda, Mandala 8, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AE.%E0%A5%AA%E0%A5%AE Sukta 48].</ref></blockquote>The duration of daylight, reckoned from sunrise to sunset, was divided into two parts called pūrvāhṇa (forenoon) and aparāhṇa (afternoon), three parts called, pūrvāhṇa, madhyāhna, and aparāhṇa, four parts called pūrvāhṇa madhyāhna, aparāhṇa and sāyāhna,4 and five parts called prātaḥ, saṅgava, madhyāhna, aparāhṇa, and sāyāhna (Śatapatha-brāhmaṇa, 2. 2. 3. 9).<blockquote>आदित्यस्त्वेव सर्व ऋतवः । यदैवोदेत्यथ वसन्तो यदा संगवोऽथ ग्रीष्मो यदा मध्यन्दिनोऽथ वर्षा यदापराह्णोऽथ शरद्यदैवास्तमेत्यथ हेमन्तस्तस्मादु मध्यंन्दिन एवादधीत तर्हि ह्येषोऽस्य लोकस्य नेदिष्ठं भवति तन्नेदिष्ठादेवैनमेतन्मध्यान्निर्मिमीते - २.२.३.[९]<ref>Shatapatha brahmana, Kanda 2, Adhyaya 2, [https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A4%A4%E0%A4%AA%E0%A4%A5%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A8/%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3_%E0%A5%A9 Brahmana 3].</ref></blockquote>Of these names the first three occur in Ṛgveda, 5. 76. 3; <blockquote>उता यातं संगवे प्रातरह्नो मध्यंदिन उदिता सूर्यस्य । दिवा नक्तमवसा शंतमेन नेदानीं पीतिरश्विना ततान ॥३॥<ref>Rgveda, Mandala 5, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AB.%E0%A5%AD%E0%A5%AC Sukta 76].</ref></blockquote>and sāyam (evening) occurs in Ṛgveda, 8. 2. 20;  <blockquote>मो ष्वद्य दुर्हणावान्सायं करदारे अस्मत् । अश्रीर इव जामाता ॥२०॥<ref>Rgveda, Mandala 8, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%AE.%E0%A5%A8 Sukta 2].</ref></blockquote>10. 146. 3, 40.<blockquote>उत गाव इवादन्त्युत वेश्मेव दृश्यते । उतो अरण्यानिः सायं शकटीरिव सर्जति ॥३॥<ref>Rgveda, Mandala 10, [https://sa.wikisource.org/wiki/%E0%A4%8B%E0%A4%97%E0%A5%8D%E0%A4%B5%E0%A5%87%E0%A4%A6%E0%A4%83_%E0%A4%B8%E0%A5%82%E0%A4%95%E0%A5%8D%E0%A4%A4%E0%A4%82_%E0%A5%A7%E0%A5%A6.%E0%A5%A7%E0%A5%AA%E0%A5%AC Sukta 146].</ref></blockquote>Kauṭilya (Arthaśāstra, 1.19), Dakṣa, and Kātyāyana divided the day and night each into eight parts.<blockquote>नालिकाभिरहरष्टधा रात्रिं च विभजेत् । छाया-प्रमाणेन वा ।। ०१.१९.०६ ।।<ref>Arthashastra, Adhikarana 1, [https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A7/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A7%E0%A5%AF Adhyaya 19].</ref></blockquote>The days and nights were also divided into 15 parts each, and these parts were called muhūrta. The muhurtas falling during the days of the light and dark fortnights as well as those falling during the nights of the light and dark fortnights were given specific names (Taittirīya-brāhmaṇa, 3. 10. 1. 1–3). The fifteen days and nights of the light fortnight as well as the fifteen days and nights of the dark fortnight were also assigned special names (Taittirīya-brāhmaṇa, 3. 10. 1. 1–3; 3. 10. 10. 2).<ref name=":0">Taittiriya brahmana, Kanda 3, [https://sa.wikisource.org/wiki/%E0%A4%A4%E0%A5%88%E0%A4%A4%E0%A5%8D%E0%A4%A4%E0%A4%BF%E0%A4%B0%E0%A5%80%E0%A4%AF%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D_(%E0%A4%B5%E0%A4%BF%E0%A4%B8%E0%A5%8D%E0%A4%B5%E0%A4%B0%E0%A4%AA%E0%A4%BE%E0%A4%A0%E0%A4%83)/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%83_%E0%A5%A9/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%AA%E0%A4%BE%E0%A4%A0%E0%A4%95%E0%A4%83_%E0%A5%A7%E0%A5%A6 Prapathaka 10].</ref>

On the analogy of a civil day, a lunar day was also sometimes reckoned from one moonrise to the next and the name tithi was given to it (Aitareyabrāhmaṇa, 32. 10). <blockquote>तदाहुर्यद्दर्शपूर्णमासयोरुपवसति न ह वा अव्रतस्य देवा हविरश्नन्ति तस्मादुपवसत्युत मे देवा हविरश्नीयुरिति। पूर्वां पौर्णमासीमुपवसेदिति पैङ्ग्यमुत्तरामिति कौषीतकं या पूर्वा पौर्णमासी साऽनुमतिर्योत्तरा सा राका। या पूर्वाऽमावास्या सा सिनीवाली योत्तरा सा कुहूः। यां पर्यस्तमियादभ्युदियादिति सा तिथिः। पूर्वां पौर्णमासीमुपवसेदनिर्ज्ञाय पुरस्तादमावास्यायां चन्द्रमसं यदुपैति यद्यजते तेन सोमं क्रीणन्ति तेनोत्तरामुपवसेदुत्तराणि ह वै सोमो यजते सोममनु दैवतमेतद्वै देवसोमं यच्चन्द्रमास्तस्मादुत्तरामुपवसेत्॥7.11॥ (32.10) (134)<ref>Aitareya brahmana, [https://sa.wikisource.org/wiki/%E0%A4%90%E0%A4%A4%E0%A4%B0%E0%A5%87%E0%A4%AF_%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%AA%E0%A4%9E%E0%A5%8D%E0%A4%9A%E0%A4%BF%E0%A4%95%E0%A4%BE_%E0%A5%AD_(%E0%A4%B8%E0%A4%AA%E0%A5%8D%E0%A4%A4%E0%A4%AE_%E0%A4%AA%E0%A4%9E%E0%A5%8D%E0%A4%9A%E0%A4%BF%E0%A4%95%E0%A4%BE) Panchika 7].</ref></blockquote>The use of the term tithi in the sense in which it is used now occurs in the Vedāṅga-jyautiṣa (Ārca-jyautiṣa, 20, 21, 31; Yājuṣa-jyautiṣa, 20–23, 25, 26). It does not occur in the vedic saṃhitās and brāhmaṇas, but there are reasons to believe that tithis were used even in those times.<ref name=":1" />

On the analogy of a civil day, a lunar day was also sometimes reckoned from one moonrise to the next and the name tithi was given to it (Aitareyabrāhmaṇa, 32. 10). <blockquote>तदाहुर्यद्दर्शपूर्णमासयोरुपवसति न ह वा अव्रतस्य देवा हविरश्नन्ति तस्मादुपवसत्युत मे देवा हविरश्नीयुरिति। पूर्वां पौर्णमासीमुपवसेदिति पैङ्ग्यमुत्तरामिति कौषीतकं या पूर्वा पौर्णमासी साऽनुमतिर्योत्तरा सा राका। या पूर्वाऽमावास्या सा सिनीवाली योत्तरा सा कुहूः। यां पर्यस्तमियादभ्युदियादिति सा तिथिः। पूर्वां पौर्णमासीमुपवसेदनिर्ज्ञाय पुरस्तादमावास्यायां चन्द्रमसं यदुपैति यद्यजते तेन सोमं क्रीणन्ति तेनोत्तरामुपवसेदुत्तराणि ह वै सोमो यजते सोममनु दैवतमेतद्वै देवसोमं यच्चन्द्रमास्तस्मादुत्तरामुपवसेत्॥7.11॥ (32.10) (134)<ref>Aitareya brahmana, [https://sa.wikisource.org/wiki/%E0%A4%90%E0%A4%A4%E0%A4%B0%E0%A5%87%E0%A4%AF_%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%AA%E0%A4%9E%E0%A5%8D%E0%A4%9A%E0%A4%BF%E0%A4%95%E0%A4%BE_%E0%A5%AD_(%E0%A4%B8%E0%A4%AA%E0%A5%8D%E0%A4%A4%E0%A4%AE_%E0%A4%AA%E0%A4%9E%E0%A5%8D%E0%A4%9A%E0%A4%BF%E0%A4%95%E0%A4%BE) Panchika 7].</ref></blockquote>The use of the term tithi in the sense in which it is used now occurs in the Vedāṅga-jyautiṣa (Ārca-jyautiṣa, 20, 21, 31; Yājuṣa-jyautiṣa, 20–23, 25, 26). It does not occur in the vedic saṃhitās and brāhmaṇas, but there are reasons to believe that tithis were used even in those times.<ref name=":1" />