Seasons are the most remarkable divisions of the year owing to the annual motion of the sun. In order to explain them clearly it is desirable that we should first of all mention some facts of modern astronomy relating to the sun's annual motion. On the 21st March, the sun's declination as well as right ascension are both zero; from 21st March to 21st June, his northerly declination increases from zero to 23 1/2 and the right ascension also increases from zero to 90°; from 21st June to 23rd Sept., the northerly declination decreases from 23 ½ to zero, while the right ascension increases from zero to 180°; from 23rd Sept. to 21st December, the southerly declination increases from zero to 23 ½ , while the right ascension increases from 180 to 270°; from 21st Dec. to 21st March, the southerly declination decreases from 23 ½ ° to zero and the right ascension increases from 270° to 360°. The dates used are approximate ones. Near the epochs at which the declination is maximum, it changes very slowly. These are called solstices. Now since on the 21st of March, the declination of the sun is zero, his diurnal path will coincide with the equator, assuming that during that day there is no change of declination. Accordingly, the period during which the sun is above the horizon will be equal to the period during which he is below the horizon on that day. Thus, there will be equal day and night, throughout the earth, The same will be the case on the 23rd of Sept. These are called equinoxes. The line joining the positions of the sun at these epochs is the line of equinoxes. These four periods have got some peculiar characteristics. In northern latitudes from 21st March to 21st June the sun remains longer above the horizon than he is below it, during one solar day, and the days are, therefore, longer than the nights, the 22nd (or 21st) of June being the longest day. The opposite is the case in southern latitudes. Admitting that the accumulation of heat during the day bears some proportion to the duration of day-light and that the loss of heat during the night bears similar proportion to the duration of night, it is concluded that there will be continuous accumulation of heat during this period and that the period from 21st June to 23rd Sept., when also the days are longer than the nights in northern latitudes, will be hotter than the ones from 22nd March to 21st June, for the latter is preceded by winter (as will be shown presently), while the former is preceded by warm weather. Thus the period from 21st June to 23rd September is called Summer and the previous period, Spring. Again, from 23rd September to 21st December as well as from 21st December to 21st March (in northern latitudes), the sun remains longer below the horizon, the nights are longer than the days; hence there will be continuous loss of heat, so that these two periods will be colder than the rest of the year. Moreover, the second period will be colder than the first; for while the second period is preceded by one which is already cold, the first is preceded by hot weather. Accordingly, the period from 21st December to 21st March is called Winter and that from 23rd September to 21st December is Autumn. Thus it is seen that the variation in the length of the day during the year causes a variation in the seasons and that the sun's annual motion is the cause of the seasons [1]. However, it may be mentioned here that the Indian seasons are not four but six in number, viz., Grisma, Varsa, Sarat, Hemanta, Sita and Vasanta. Hence it is obvious that the seasons forming different epochs of one year determines the period of the year. Had there been no seasons, the period of the year would not have been determined; this is clear from the fact that a year began to be reckoned from one Summer, or Spring or Winter or Autumn to the next Summer or Spring or Winter or Autumn respectively when twelve lunar months were complete.
The Rgveda says that the sun is the cause of the terrestrial seasons[2] . In another place it is more explicit. It says, "They (the sun and moon) walk by their own power, one after the other (or from east to west), as playing children they go round the sacrifice. The one looks upon all the worlds, the other is born again and again, determining the seasons."[3]
That the seasons were six in numb is mentioned several times in the Rgveda, and also their names are given in order in the Taitthaya Samhita [4]. But in some places the number is given as five.[5] Here the Hemanta (dewy season) and the Sisira (Winter) were combined into one. This is explicitly mentioned in the Aitareya Brahmana-"there are five seasons owing to the combination of Hemanta and Sisira." That an attempt was made in the Taittiriya Samhita, Taittiriya Brahma?a, Satapatha Brahma?a to combine the Hemanta and Sisira is shown in the Kalamadhava.[6] However, there are passages in the Satapatha Brahma?a where a variation in the number is mentioned. The general tendency was to fix the number at six [7]. The following is significant in this connection :-"The Spring, the Summer, and the Rains, these seasons represent the gods; and the Autumn, the Winter, and the dewy season represent the fathers." [8] The months of the six seasons are thus mentioned :-Madhu and Madhava are the Spring months when plants sprout and trees are brought to ripeness; Sukra and Suci are the Summer months, when the sun burns fiercest (Sukra means clear and Suci bright); Nabhas and Nabhasya are the months of the rainy season (Nabhas means mist or cloud); Isa and Urja are the Autumn months because in the Autumn food (Urja) and juice (plants) ripen; Sahas and Sahasya are the Winter months, because the Winter by force brings these creatures into his power; Tapas and Tapasya are the months of the dewy season, because during these months it freezes most severely.[9] In another passage it is said, "Rathagritsa and Rathaujas are the two Spring months, Rathasvana and Rathecitra are the two Summer months ; Rathaprota and Asamaratha are the two rainy months; Tarksya and Aristanemi are the two Autumn months; Senajit and Susena are the Winter months ; Tapas and Tapasya are the two dewy months[10]. There are several passages in the Satapatha Brahma?a where five seasons are mentioned [11]. In this calculation the dewy season (Hemanta) is omitted.[11] In one place the number is given as three[12], probably each season consisting of four months. It is interesting to note in this connection that mention has been made of seven seasons in a year in the Satapatha Brahma?a [13]. In viii. 5. 4. 9. 10 after the mention of seven seasons rather a vague explanation has been sought to be given but in conclusion it has been remarked, "but indeed there are six seasons." In another place an attempt has been made to explain it further; in verses 9 to 14 (x. 2.5) the six seasons (Spring, Summer, rainy season, Autumn, Winter and dewy season) are described and then it is said that in addition to these there are three days,--the days and nights of that thirteenth and intercalary month, which form the seventh season.
The system of nomenclature beginning with Madhu and Madhava had been in vogue for a long time before it was replaced by the system of Caitra, Vaisakha, etc. When did this system come into use? From the time when the Spring season was known to begin in Caitra. That Caitra and Vaisakha were the Spring months is mentioned in the Pura?as and the Mahabharata, but in later books Phalguna and Caitra are said to be the Spring months. But nowhere in Indian literature Vaisakha and Jyaistha are mentioned as the Spring months and Caitra a month of the dewy season. Thus it is seen that at first Caitra and Vaisakha were the Spring months. In still earlier times Madhu and Madhava came to be synonymous with Caitra and Vaisakha. In our present system Phalguna and Caitra are the Spring months. It is, therefore, clear that the Spring season has receded roughly by two months and this could be caused in 4,300 years approximately. Thus the system of nomenclature, Caitra, Vaisakha, etc, came into use as early as 2000 years before the Saka era.[14] Vasanta was considered to be the first of the seasons, and the agrayanestis or the half yearly sacrifices were required to be performed every Vasanta(Spring). The Taittiriya Brahma?a remarks that Vasanta is the "mouth of the seasons";[15] upon this the author of Kalamadhava observes "samvatsaropakramarupatvena vasantasya prathamyam drastayyam." [16] It will be necessary to remind here that the Phalguni full-moon was regarded as the "mouth of the year."[17] In the Taittiriya Brahma?a the year has been compared to a bird, Vasanta (Spring) is the head, Grisma (Summer) is the right wing, Varsa (rainy season) is the tail, Sarat (Autumn) the left wing, and Hemanta (dewy season) is the middle part.[18] Here the Winter season has been left out.
About the division of the seasons Satapatha Brahma?a says, "After Prajapati had created the living beings, his joints (parvan) were released. Now Prajapati, doubtless, is the year and his joints are the two junctions of day and night (i.e., the twilights), the full moon and new-moon, and the beginning of the seasons. He was unable to rise with his relaxed joints; and the gods bealed him by means of these havis-offerings; by means of the Agnihotra they healed that joint which consists of the two joints of day and night, joined that together; by means of the full-moon and new-moon sacrifice they healed that joint which consists of the full and new moon, joined that together and by means of the three caturmasyas (seasonal offerings) they healed that joint which consists of the beginnings of the seasons, joined that together.[19] This shows that the division of the seasons was at first felt necessary for regulating the seasonal sacrifices.
The passage from the Taittiriya Samhita quoted above states that the Citra and Phalguni full moons were the beginnings of the year. But why should the Citra and the Phalguni full moon be called the beginnings of the year? Saya?a thinks that they were so described because they occurred during Vasanta or the first of the seasons. This view Sayana propounds in his commentary on Taittiriya Samhita, vii. 4.8. Tilak does not consider the explanation satisfactory and he says, "According to all astronomical works Sisira commenced with the Winter solstice, and the three seasons of Sisira, Vasanta and Grisma were comprised in the Uttaraya?a as it was then understood. Now in the days of the Taittiriya Samhita the Winter solstice fell in the month of Magha, and Magha and Phalguna were therefore comprised in Sisira, and Caitra and Vaisakha in Vasanta. But in order that Sayana's explanation might be correct Phalguna must fall in the Vasanta season which as a matter of fact, it did not.[20] Saya?a, in his commentary on the Baudhayanasutra and also in the Kalamadhava (Cal. ed., pp. 60-61), tried to get rid of this difficulty by proposing a double Vasanta--lunar and solar, the lunar to include the months of Phalguna and Caitra, and the solar those of Caitra and Vaisakha, quoting amongst others Rv., X. 85. 18, as an authority to show that the seasons were regulated by the moon. Tilak remarks on this theory of two-fold seasons of Sayana : "The authorities quoted by Saya?a are not explicit and sufficient to maintain the two-fold character of the seasons. It is true that the months in the calendar were all lunar, but the concurrence of the lunar and the solar year was always secured by inserting an intercalary month whenever necessary. Under such a system lunar seasons can have no permanent place. Now and then lunar months ceased to correspond with the seasons they represented, but this was at once set aright by the introduction of an intercalary month." Therefore, according to Tilak, if we exclude the correction due to the precession of the eqinoxes, which was too minute to be noticed till after hundreds of years, there was thus no reason why the lunar seasons should come to be regarded as a permanent institution. Moreover, a lunar year is shorter than the solar by 11 days. Hence, if the solar Vasanta commences on the 1st day of the lunar Caitra month this year, it will commence on the 12th day of Caitra (lunar) next year and 11 days later still in the third year, when by the introduction of an intercalary month the commencement of Vasanta will again be brought back to the Ist day of Caitra, thus showing that the two-fold character of the seasons may delay the beginning of Vasanta to Vaisakha (lunar), but the season cannot be advanced and brought back to Phalguna. No doubt, in the 14th century when Saya?a flourished, the Vasanta season commenced, as it does now, in the month of Phalguna; but it was so because of the Winter solstice having receded by over full one month by that time. This was not understood by Sayana and hence he attempted to reconcile the difference on the theory of two-fold character of the seasons. Moreover, several Brahma?as and Sutras pronounce the full-moon night of the month of Phalguna to be the first night of the year. Satapatha Brahmana (vi. 2. 2. 18) says, "the Phalguni full-moon is the first night of the year; the Taittiriya (I. 1. 2. 8) and the Sánkhayana (iv. 5; V. 1) Brahmanas contain similar passages, while the Gopatha (i. 19) after stating that the Uttara and the Purva Phalguni are respectively the beginning and the end of the year, adds “just as the two ends of a thing meet so these two termini of the year meat together." The Tandya Brahma?a (v. 9) also says the same thing.
Thus it is seen that in the early Vedic times the year began when the sun was in the vernal equinox; and as the sun then passed from the south to the north of the equator it was also the commencement of his northern passage. In other words, the Uttaraya?a (according to the several astronomical works, Uttaraya?a is the period of the year from the Winter to the Summer solstice[21]), Vasanta, the year and the satras all commenced together at the vernal equinox. The autumnal equinox which came after the rains was the central day of the year ; and the latter half of the year was named the Pitryana or what is called now the Daksinayana. Later on, the commencement of the year was changed from the vernal equinox to the Winter solstice. It is difficult to ascertain definitely the time of the change. But the change must have been introduced long before the vernal equinox was in the Krttikas, and when this change was made Uttaraya?a must have gradually come to mean the first half of the new year, i.e., the period from the Winter to the Summer solstice. Now the Vedanga Jyotisa makes the year commence with the Winter solstice, and there are passages in the Srauta Sutras which enjoin that the annual sacrifices like the Gavam-ayana, should be commenced at the same time[22]. The Vedanga Jyotisa gives the following positions of the solstices and equinoxes :-(a) The Winter solstice in the beginning of Sravistha (Dhanistha), (b) the vernal equinox in 10° of Bharani or the beginning of the Krttikas, (c) the Summer solstice in the middle of Aslesa, and (d) the Autumnal equinox in 3° 20' of Vaisakha. Thus the first year of the cycle commenced with the Winter solstice when the sun and the moon were together at the beginning of Dhanistha and the Uttarayana also began at the same time. Taking the data given in the Vedanga Jyotisa as his basis, the late Krsna Sastri Godbole has thus calculated the position of the four cardinal points of the ecliptic, when the Winter solstice as stated in the Brahmanas, occurred on the full-moon day in the month of Phalguna :-(a) the Winter solstice in 3° 20' of the divisional Uttara Bhadrapada, (b) the vernal requinox in the beginning of Ardra, (c) the Summer solstice in 10° of Uttara Phalguni, and (d) the Autumnal equinox in the middle of Mula.
The four cardinal points have been thus defined by Suryasiddhanta[23]. - "In the middle of the starry sphere, the equinoxes are diametrically opposed, so are the two solstices (in the ecliptic).”
Now to understand this change in the beginning of the year, it is necessary to remember that the solar year was sidereal and not tropical [24] and that the great object of the calendar was to ascertain the proper time of the seasons. This necessitated a change in the beginning of the year, every two thousand years or so, to make it correspond with the cycle of natural seasons. The difference between the sidereal and the tropical year is 20-4 minutes, which causes the seasons to fall back nearly one lunar month in about two thousand years, if the sidereal solar year be taken as the standard of measurement.
Therefore, the beginning of the year was twice altered owing to the precession of the equinoxes, and there are sufficient materials in Indian literature to indicate the intermediate changes. The tradition of Rudra killing Prajapati, the god of time, for receding towards his daughter Rohini, described in the Aitareya Brahmana,[25] and later in the Satapatha Brahmana,[26]" can be interpreted as suggesting the great surprise felt at the first notice of these changes. The ancient Hindus, who observed the fact as they watched the Naksatras at the commencement of the year, could not account for the change, and they rightly and honestly believed that it was a great calamity that the sun or Prajapati (yajna or the year) should thus follow an unprecedented course. Prajapati, however, was left to be punished for his unusual conduct, and there the matter ended for the time
being. But the question was again taken up when the equinox had receded to the Krttikas. The seasons had fallen back by one full month and the ancient Hindus altered the year-beginning from the Phalguni to the Magha full-moon, while the list of Naksatras was made to commence from the Krttikas, instead of from Agrahaya?a. This was quietly done, because the calendar was mainly used for sacrificial purposes, and when it was actually observed that the sun was in the Krttikas, and not in the Margasiras, when day and night were equal, the commencement of the year was altered to the Krttikas, specially as it was more convenient to do so at that time when the cycle of seasons has fallen back by one month. But it is doubtful whether the real cause was discovered or any attempt was made for the discovery. The third change was introduced by the Vedanga Jyotisa, when the seasons had further receded by a fortnight and not by a month. The beginning of the month was altered from the full-moon to the new-moon during this period, and when this change was effected in the beginning of the month, the year was made to commence, owing to the falling back of the seasons by a fortnight, with the new-moon in Dhanistha, as the Vedanga Jyotisa has done. The next change was introduced and put into effect by Varahamihira in the beginning of the 6th century A.C. when the list of the Naksatras was made to begin with Asvini. There is, however, the record of an intermediate attempt to reform the calendar in the Mahabharata [27] and this attempt which proved abortive was made when it was noticed that the seasons had again receded by a fortnight. In the 7Ist chapter of Adiparvan it is narrated that Visvamitra attempted to create a new world and to make the Naksatras begin with Sravana, instead of Dhanistha, and this story also occurs in the 44th chapter of Asvamedhaparvan. This tradition can also be found in other Puranas where Visvamitra is represented as endeavouring to create a new celestial sphere. It appears, however, that he did not succeed, and the Krttika system as modified by the Vedanga Jyotisa continued to regulate the calendar until Varahamihira made the list of Naksatras begin with Asvini and this last system is even now being used[28].
In Varahamihira's time the vernal equinox coincided with the end of Revati and the Summer solstice with Punarvasu; but in two places Varahamihira has distinctly referred to the older position of the solstices recorded by writers who preceded him. In the Pancasiddhantika he says, "when the return of the sun took place from the middle of Aslesa, the tropic (ayana) was then correct. It now takes place from Punarvasu."[29] Again in the Brhatsamhita,[30] he mentions the same older position of both the solstitial points and appeals to his readers to ascertain by actual observation which of the two positions of the solstices is the correct one, whether older position of the solstices or the position given by himself. Now in the days of Varahamihira the change introduced by the Vedanga Jyotisa was in vogue and, therefore, there existed works which placed the Winter solstice in the beginning of (divisional) Dhanistha and the Summer solstice in the middle of Aslesa. In corroboration of the statement by Varahamihira Bhattotpala in his commentary on Brhatsamhita, chapter iii, verse I, quotes Garga as follows :- “sravisthadyat pausnardham caratah sisirah.” This is further corroborated by other quotations by later commentators from the works of Garga and Parasara.[31] This proves, without doubt, that the system in which the year commenced with the month of Magha, i.e., from the winter season was once actually in vogue. Amarasimha states that the seasons were comprised of two months each, beginning with Magha and three such seasons make one ayana.[32] In the Mahabharata[33] it is related that Bhisma, who possessed the superhuman power of choosing the time of his death, was awaiting on his deathbed for the return of the sun towards the north from the Winter solstice and that this event took place in the first half of the month of Magha. It is, therefore, clear that the Winter Solstice coincided in those days with the beginning of Dhanistha, and this must have been the case as the calendar modified by the Vedanga Jyotisa, which made the year begin with the Winter solstice in the month of Magha when the sun and the moon were together at the beginning of Dhanistha and when the Uttaraya?a also began, was in vogue.
Thus we find that in the days of the Rgveda at the vernal equinox, when the day and night were equal, the sun was in the Mrgasiras and according to Tilak the sun was at first in the Punarvasu; at the time of the Aitareya Brahmana the sun was then in the Rohini or in the Krttikas just preceding Rohini; and at the time of the Taittiriya Samhita and the later Brahma?as the sun was distinctly in the Krttikas at the vernal equinox. In the Vedanga Jyotisa the first year of the cycle began with the Winter solstice when the sun and the moon came together at the beginning of Sravistha (Dhanistha), then it was the new-moon of the month of Magha and the Uttarayana began; the Daksinayana or southerly motion of the sun began in the month of Sravana when the sun was in the middle of Sarpa or Aslesa and the moon was in Citra. During the Uttarayana, i.e., during the period of the year from the Winter to the Summer solstice the duration of day (i.e., the period during which day-light lasts) increases and that of night decreases; the reverse takes place during the Daksinayana journey of the sun. But Tilak denies the fact that the year could at any time begin with the Winter solstice. He says that a closer consideration of the ceremonies performed in the yearly satras (sacrifices) will show that the Winter solstice could never have been the original beginning of these sutras. "The middle day of the annual satra is called the Visuvan day, and it is expressly stated that this central day divides the satra into two equal halves, in the same way as the Visuvan or the equinoctial day divides the year[34]. The satra was thus the imitation of the year in every respect, and originally it must have corresponded exactly with the course of the year. Now, as Visuvan literally means the time when day and night are of equal length, if we suppose the year to have at the time commenced with the Winter solstice, the Visuvan or the equinoctial day could never have been its central day, and the middle day of the satra would correspond not with the equinoctial, as it should, but with the Summer solstice.[35]" Here we find that Tilak's main argument was based on the fact that if the year began with the Winter solstice Visuvan would then divide the year in the proportion of 3 to 9, i.e., three months on one side of the Visuvan and nine on the other, instead of Visuvan being the central day. It has been said in the beginning that Vasanta was regarded in the Vedic times the first season of the year. Probably there were only three seasons-Grisma, Varsa and Hemanta-at the time of the Rgveda. In fact, these are the three seasons of India. The Satapatha Brahma?a has also in one place mentioned only three seasons. Regarding the Uttaraya?a and Daksinayana paths of the sun, the Satapatha Brahmana lays down that "Vasanta, Grisma and Varsa are the seasons of the Devas, Sarat, Hemanta and Sisira those of the Pitrs, the increasing fortnight is of the Devas, the decreasing one of the Pitrs, the forenoon is of the Devas, the afternoon of the Pitrs. When the sun turns to the north he is amongst the Devas and protects them, when he turns to the south he is amongst the Pitrs and protects them.[36] This shows clearly that the Uttarayana of the sun began from the vernal equinox and was for six months, and the Daksinayana began from the autumnal equinox and was also for six months. But in course of time the Uttarayana came to mean the period of the year from the Winter to the Summer solstice, that is the period from the time when the sun turns towards the north till it returns towards the south. This might have been a mistake as Tilak said, but this was the view held by the Vedanga Jyotisa. At a later period, however, the year was again made to begin from the vernal equinox.
Next we come to the period of the Samhitas. Varahamihira in his Brhat Samhita, while giving the reason for his writing the book says that he will compile in a summary form the views lying scattered in the various samhitas written by the ancient authors. Therefore, it may be safely inferred that much of the B?hatsamhita, if not the whole, was taken from the ancient Samhitas.[37] There we find that the Samhitas recognised six seasons to comprise the year which began with Sisira (Winter) and that the year commenced with the beginning of the Uttarayana journey of the sun. In the Brhatsamhita (Aditya-caradhyaya) Sisira (winter) has been mentioned as the first season of the year. This meant that the year began with the Winter solstice. Bhattotpala, the commentator, has in his commentary on the above passage of the Brhatsamhita, given a table for the months of the seasons prevalent at the time of the old Samhitas. In the Brhatsamhita (Utpatadhyaya, verse 84) Varahamihira has mentioned Madhu and Madhava as the Spring months. But then spring comprised the two months Caitra and Vaisakha. Therefore, Winter must have begun from Magha and the year beginning with Winter must necessarily have commenced from Magha. This was the change introduced by the Vedanga Jyotisa which made the year commence with the Winter solstice and this was in vogue till the time of Varahamihira. He found that in his time the vernal equinox coincided with the end of Revati and the Summer solstice with Punarvasu. In the Pancasiddhantika he remarks, "when the return of the sun took place from the middle of Aslesa, the tropic was then correct. It now takes place from Punarvasu." Varahamihira, therefore, introduced a change in the year beginning and made the list of Naksatras commence with Asvini. The year was then, again, made to begin with the vernal equinox, and it was from that time that the Spring season came to comprise the two months Phalguna and Caitra. This modified year-beginning introduced by Varahamihira has since then been current in India and is even now regarded as the correct year beginning.
Now one thing still remains to be discussed. Why is the year called Varsa? There must have some connection with Varsa (rainy season), and it is surmised that the year must have come to acquire this denomination from the fact of the year beginning with Varsa or rainy season at some time or other; that is, the year must have been made to begin with the commencement of the Daksinayana course. But this is found neither in the Vedas nor in the later Brahmanas and Samhitas, nor is there any mention of this fact in the Vedanga Jyotisa. However, Kautilya, in his Arthasastra, says that the year in his time began with the Summer solstice at the end of Asadha[38]. A detailed explanation is found in the Suryaprajnapti where an account of the seasons is given. There it is said that the seasons commence with the Asadha month, though the cycle of five years commences with the 1st day of the dark half of the month of Sravana. Suryaprajnapati was written by Mahavira and this is the only astronomical work of the Jaina astronomers which is now available. The Surya-prajnapati mentions the seasons as follows:---the Rains, the Autumn, the dewy season, the Spring, and the Summer. Here we notice that Hemanta and Sisira have been combined into one and the seasons are five in number. The year has been made to begin with the rainy season. It is then stated that the seasons are of two kinds, the solar and the lunar. The solar season is equal to two solar months or 61 days, but the cold season has got four months. Regarding the lunar seasons it is said that in one sidereal revolution of the moon, the lunar seasons are six. Hence in the cycle of 5 years which is equal to 67 sidereal revolutions of the moon there are 6x67 = 492 lunar seasons. In one lunar season there are 4() days. The reason for this is as follows :-One sidereal revolution of the moon=6 seasons. Now one sidereal revolution is equal to 27() days. Therefore, one season is equal to 27()/6= 4()days.
Now let us come to the description of the seasons in the astronomical Siddhantas. We have already said that Varahamihira made the year begin with the vernal equinox in the months of Phalguna. But in the Suryasiddhanta the year has been described to begin with the Winter solstice. Suryasiddhanta says, "from the Winter solstice, the periods during which the sun remains in two signs are the seasons named successively :-(1) Sisira (very cold), (2) Vasanta (spring), (3) Grisma (hot), (4) Varsa (rainy season), (5) Sarat (Autumn) and (6) Hemanta (cold). This clearly shows that the Suryasiddhanta used the system which was in vogue before the time of Varahamihira and it was the system introduced by the Vedanga Jyotisa. There is, therefore, no doubt that this portion of the present Suryasiddhanta which exactly tallies with the description given in the text of the Suryasiddhanta included in Varahamihira's Pancasiddhantika, must have come down from the ancient Saurasiddhanta. However, Bhaskara begins the seasons from Vasanta and in giving a descriptive account of the six seasons he has indulged his love for poetry, endeavouring to write something calculated to satisfy the fancy of men of literary taste.[39]
We have thus given in detail the traditional year-beginnings along with the seasons recorded in the Vedic literature, in the Vedanga Jyotisa and the later Siddhanta works. This is a continuous record of the year beginnings from the oldest time down to the present ay in the religious as well as astronomical literature of India. This account of the successive attempts of the ancient Hindus for regulating the calendar so that the year might concur with the seasons, gives a conclusive proof of their sound knowledge of the astronomical phenomena like the procession of the equinoxes and is a living testimony to their keen interest for and deep insight into the changing mysteries of the heavens.
References
1 Vide Dr. D. N. Mallik's "Elements of Astronomy," pp. 92, 93.
2 Rgveda, i. 75.
3 Rgveda, X. 85. 18.
4 Tait. Samhita, IV. 3. 2; V. 6. 23 ; VII. 5. 14.
5 Tait. Br., ii. 7. 10; Ait. Br., i. I.
6 Madhavacarya's Kalamadhava, Rtunirnaya section.
7 Satapatha Brahma?a, iii. 4. 3. 17; iii. 6. 4. 19; iv. 4. 5. 18; v. 5. 2. 4; vi. 3. 2. 10; vi. 7. 1. 18.
8 Satapatha Brahma?a, ii. 1. 3. 3.
9 Satapatha Brahma?a, iv. 3. I. 14-19; Tait. Samhita, 4. 11.
10 Satapatha Brahma?a, viii, 6. I. 16-21.
11 Ibid., ii. I. 12; iii. I. 45. 10; iii. 3. 3.5. iii, 9. 4. 11; iii. 6. 4. 18; iv. 1. 1. 16. iv. 5. 5. 12; vi, 2. 2.8; vii. 2. 3. 9; viii. 4. 1. 11; ix, 2. 1, 10; xi. 7. 4.4
12 Ibid., ii. 2. 3. 9.
13 Ibid., iii. 4. 4. 17.
14 Sat.Br., vi. 6. 1. 14; vi.6. 2. 7; viii. 4. 1. 23; ix.1.2.3; ix, 2. 3. 45.
15 Vide Prof. Jogesh Chandra Roy's "Our Astronomy and Astronomers," p. 161.
16 Tait. Brahma?a, i. I. 2. 6.
17 Kalamadhava, Calcutta Edition, p. 59.
18 Tait. Sam., vii. 4. 8.; Gopatha Br., vi, 19.
19 Tait. Br., vi. 10. 4. 1.
20 Satapatha Br., 1. 6. 3. 25-26.
21 Orion, pp. 62, 63.
22 Suryasiddhanta, chap. xiv, 10; Vedinga Jyotiga, 5.
23 Vedanga Jyotisa, 5: Asvalayana-Srauta-sutra, i. 2. 14. I; ii. 2. 14. 3 and 22; Katyayana. Srauta-sutra, v, I. I.
24 Suryasiddhanta, chap. xiv, verse 7.
25 The sidereal year was used even in the Suryasiddhanta, though the motion of the equinoxes was then discovered. Suryasiddhanta, I, 13.
26 Ait. Br., iii. 33.
27 Sat. Br., i. 7. 4. I.
28 Mahabharata, Adiparvan, chap. 71, verse 34.
29 Mahabharata, Asvamedhaparvan, chap. 44, verse 2.
30 Tilak's Orion, pp. 212-216.
31 Pancasiddhantika, edited by Thibaut and Sudhakar Dvivedi.
It has as follows:-
Aslesardhad asid yada nivrtti? kilosnakira?asya/
Yuktam ayanam tadasit sampratam ayanam punarvasutah//
32 Brhatsamhita, chap. iii, 1 and 2.
33 Garga quoted by Somakara on Vedanga Jyotisa, verse 5.
34 Amarasimha, i. 4. 13. "dvau dvau maghadimasau syadrtus tairayanam trivih."
35 Mahabharata, Anusasanaparvan, chap. 167, verses 27 and 28.
36 Ait. Br., iv, 22; Taitt. Br., i. 2. 3. I; Tandya Br., iv. 7. 1.
37 Tilak's Orion, p, 21.
38 Satapatha Brahmana, ii. I. 3. I.3.
39 Prof. Jogesh Chandra Roy's "Our Astronomy and Astronomers," p. 52.