HINDU From very early times Hindus have employed luni-solar cycles made by the combination of solar years and lunar years so treated as to keep the beginning of the lunar year near that of the solar year. The detailed arrangement of the earliest form of Hindu calendar is still a subject of research but, from about A.D. 400, under the influence of the Greek astronomy, developed the Hindu calendar as known to-day.
For civil purposes, solar years are used in Bengal, Orissa and in the Tamil and Malayalam districts of Madras ; elsewhere lunar years. But everywhere the general religious rites and festivals are regulated by the lunar year and the details of private and domestic life (auspicious occasions for marriages, undertaking journeys, etc.), are based upon the lunar calendar. Even almanacs showing the solar year give details of the lunar year. The civil solar year is determined by the astronomical solar year, beginning with an artificial nominal equinox instead of with the true one.
The Solar Month.—The solar year is divided into 12 months, in accordance with the successive saiiakrantis or entrances of the sun into the (sidereal) signs of the zodiac, which, as with us, are I 2 in number. The names of the signs in Sanskrit are as follows: Mesha, the ram (Aries) ; Vrishabha, the bull (Taurus) ; Mithuna, the pair, the twins (Gemini) ; Karka, Karkata, Karkataka, the crab (Cancer) ; Sirimha, the lion (Leo) ; Kanya, the maiden (Virgo) ; Tula, the scales (Libra) ; Vrischika, the scorpion (Scor pio) ; Dhanus, the bow (Sagittarius) ; Makara, the sea-monster (Capricornus) ; Kumbha, the water-pot (Aquarius) ; and Mina, the fishes (Pisces). The solar months are known in some parts by the names of the signs or by corrupted forms of them; and these are the best names for them for general use, because they lead to no confusion. But they have elsewhere another set of names, pre serving the connection of them with the lunar months : the San skrit forms of these names are Chaitra, Vaisakha, Jyaishtha, Ashadha, 8ravana, Bhadrapada, Asvina or Asvayuja, Karttika, Margasira or Margasirsha (also known as Agrahayana), Pausha, Magha, and Phalguna : in some localities these names are used in corrupted forms, and in others vernacular names are substituted for some of them; and, while in some parts the name Chaitra is attached to the month Mesha, in other parts it is attached to the month Mina, and so on throughout the series in each case. The astronomical solar month runs from the moment of one sarnkrwnti of the sun to the moment of the next say kranti; and, as the signs of the Hindu zodiac are all of equal length, 3o degrees, as with us, while the speed of the sun (the motion of the earth in its orbit round the sun) varies according to the time of the year, the length of the month is variable : the shortest month is Dhanus ; the long est is Mithuna.
The civil days are named after the weekdays, of which the usual appellations (there are various synonyms in each case, and some of the names are used in corrupted forms) are in Sanskrit Aditya vara or Ravivara, the day of the sun, sometimes called Adivara, the beginning-day (Sunday) ; Somavara, the day of the moon (Monday) ; Mangalavara, the day of Mars (Tuesday) ; Bud havara, the day of Mercury (Wednesday) ; Brihaspativara or Guruvara, the day of Jupiter (Thursday) ; 8ukravara, the day of Venus (Friday) ; and 8anivara, the day of Saturn (Saturday). While some of the astronomical books perhaps postulate an earlier knowledge of the "lords of the days," and other writings indicate a still earlier use of the period of seven days, the first proved instance of the use of the name of a weekday is of the year A.D. 484, and is furnished by an inscription in the Saugor district, Cen tral India.
As their civil day begins at sunrise, the Hindus naturally count all their times, in gliatikds and pa/as, from that moment. But the moment is a varying one, though less in India than in European latitudes; and Hindus have recognized the necessity, in connection with their lunar calendar, of a convenient means of referring their own times to the time which prevails officially. Consequently, many almanacs have adopted the European practice of showing the time of sunrise, in hours and minutes, from midnight; and some of them add the time of sunset from noon.
The lunar year consists primarily of 12 lunations or lunar months, of which the present Sanskrit names, generally used in more or less corrupted forms, are Chaitra, Vaisakha, etc., to Phalguna, as given above in connection with the solar months. It is of two principal varieties, according as it begins with a certain day in the month Chaitra, or with the corresponding day in Kart tika : the former variety is conveniently known as the Chaitradi year ; the latter as the Karttikadi year. For religious purposes the lunar year begins with its first lunar day : for civil purposes it be gins with its first civil day, the relation of which to the lunar day will be explained below. Owing to the manner in which the begin ning of the lunar year is always shifting backwards and forwards, it is not practicable to lay down any close equivalents for com parison : but an indication may be given as follows. The first civil day of the Chaitradi year is the day after the new-moon con junction which occurs next after the entrance of the sun into Mina, and it now falls from about March 13 to about April 1 I ; the first civil day of the Karttikadi year is the first day after the new-moon conjunction which occurs next after the entrance of the sun into Tula, and it now falls from about Oct. 17 to about Nov. I 5.
The present names of the lunar months, indicated above, were derived from the nakshatras, which are certain conspicuous stars and groups of stars lying more or less along the neighbourhood of the ecliptic. The nakshatras are regarded sometimes as 27 in num ber, sometimes as 28, and are grouped in 12 sets of two or three each, beginning, according to the earlier arrangement of the list, with the pair Krittika and Rohini, and including in the sixth place Chitra and Svati, and ending with the triplet Revati, Asvini and Bharani. They are sometimes styled lunar mansions, and are sometimes spoken of as the signs of the lunar zodiac ; and it is, no doubt, chiefly in connection with the moon that they are now taken into consideration. But they mark divisions of the ecliptic : according to one system, 27 divisions, each of 13 degrees 20 min utes; according to two other systems, 27 or 28 unequal divisions, which we need not explain here. The almanacs show the course of the sun through them, as well as the course of the moon ; and the course of the sun was marked by them only, before the time when the Hindus began to use the 12 signs of the solar zodiac. So there is nothing exclusively lunar about them. The present names of the lunar months were derived from the nakshatras in the following manner : the full-moon which occurred when the moon was in con junction with Chitra (the star a Virgins) was named Chaitri, and the lunar month, which contained the Chaitri full-moon, was named Chaitra ; and so on with the others. The present names have superseded another set of names which were at one time in use concurrently with them; these other names are Madhu (= Madhava, ukra, Nabhas, Nabhasya, Isha, Urja ( = Karttika), Sahas, Sahasya, Tapas, and Tapasya ( = Phal guna) : they seem to have marked originally solar season-months of the solar year, rather than lunar months of the lunar year.
A lunar month may be regarded as ending either with the new moon. which is called amavdsya, or with the full-moon, which is called piirnamasi, purnimd: a month of the former kind is termed amanta, "ending with the new-moon," or .fukladi, "beginning with the bright fortnight" ; a month of the latter kind is termed purni manta, "ending with the full-moon," or krishnddi, "beginning with the dark fortnight." For all purposes of the calendar, the amdnta month is used in Southern India, and the purnimanta month in Northern India. But only the amanta month, the period of the synodic revolution of the moon, is recognized in Hindu astronomy, and for the purpose of naming the lunations and adjusting the lunar to the solar year by the intercalation and suppression of lunar months; and the rule is that the lunar Chaitra is the amanta or synodic month at the first moment of which the sun is in the sign Mina, and in the course of which the sun enters Mesha : the other months follow in the same way; and the lunar Karttika is the amdnta month at the first moment of which the sun is in Tula, and in the course of which the sun enters Vrischika. The connec tion between the lunar and the solar months is maintained by the point that the name Chaitra is applied according to one practice to the solar Mina, in which the lunar Chaitra begins, and according to another practice to the solar Mesha, in which the lunar Chaitra ends. Like the lunar year, the lunar month begins for religious purposes with its first lunar day, and for civil purposes with its first civil day.
One mean lunar year of 12 lunations measures very nearly 354 days 8 hrs. 48 min. 34 sec. ; and one Hindu solar year measures 365 days 6 hrs. 12 min. 3o sec. according to Aryabhata, or slightly more according to the other two authorities. (See CHRONOLOGY : Hindu.) (X.)