The Tribes and Castes of the Central Provinces of India, Volume 3

2. The apparent path of the sun. The ecliptic or zodiac

The universe may be conceived for the purpose of understanding the sun’s path among the stars as if it were a huge ball, of which looking from the earth’s surface we see part of the inside with the stars marked on it, as on the inside of a dome. This imaginary inside of a ball is called the celestial sphere, and the ancients believed that it actually existed, and also, in order to account for the varying distances of the stars, supposed that there were several of them, one inside the other, and each with a number of stars fixed to it. The sun and earth may be conceived as smaller solid balls suspended inside this large one. Then looking from the surface of the earth we see the sun outlined against the inner surface of the imaginary celestial sphere. And as the earth travels round the sun in its orbit, the appearance to us is that the sun moves over the surface of the celestial sphere. The following figure will make this clear.²¹²

Fig. 1.—The Orbit of the Earth and the Zodiac.

Thus when the earth is at A in its orbit the sun will appear to be at M, and as the earth travels from A to B the sun will appear to move from M to N on the line of the ecliptic. It will be seen that as the earth in a year makes a complete circuit round the sun, the sun will appear to have made a complete circuit among the stars, and have come back to its original position. This apparent movement is annual, and has nothing to do with the sun’s apparent diurnal course over the sky, which is caused by the earth’s daily rotation on its axis. The sun’s annual path among the stars naturally cannot be observed during the day. Professor Newcomb says: “But the fact of the motion will be made very clear if, day after day, we watch some particular fixed star in the west. We shall find that it sets earlier and earlier every day; in other words, it is getting continually nearer and nearer the sun. More exactly, since the real direction of the star is unchanged, the sun seems to be approaching the star.

“If we could see the stars in the daytime all round the sun, the case would be yet clearer. We should see that if the sun and a star were together in the morning, the sun would, during the day, gradually work past the star in an easterly direction. Between the rising and setting it would move nearly its own diameter, relative to the star. Next morning we should see that it had got quite away from the star, being nearly two diameters distant from it. This motion would continue month after month. At the end of the year the sun would have made a complete circuit relative to the star, and we should see the two once more together. This apparent motion of the sun in one year round the celestial sphere was noticed by the ancients, who took much trouble to map it out. They imagined a line passing round the celestial sphere, which the sun always followed in its annual course, and which was called the ecliptic. They noticed that the planets followed nearly the same course as the sun among the stars. A belt extending on each side of the ecliptic, and broad enough to contain all the known planets, as well as the sun, was called the zodiac. It was divided into twelve signs, each marked by a constellation. The sun went through each sign in a month, and through all twelve signs in a year. Thus arose the familiar signs of the zodiac, which bore the same names as the constellations among which they are situated. This is not the case at present, owing to the precession of the equinoxes.” It was by observing the paths of the sun and moon round the celestial sphere along the zodiac that the ancients came to be able to measure the solar and lunar months and years.

3. Inclination of the ecliptic to the equator

As is well known, the celestial sphere is imagined to be spanned by an imaginary line called the celestial equator, which is in the same plane as the earth’s equator, and as it were, a vast concentric circle. The points in the celestial sphere opposite the north and south terrestrial poles are called the north and south celestial poles, and the celestial equator is midway between these. Owing to the special form of the earth the north celestial pole is visible to us in the northern hemisphere, and marked very nearly by the pole-star, its height above the horizon being equal to the latitude of the place where the observer stands. Owing to the daily rotation of the earth the whole celestial sphere seems to revolve daily on the axis of the north and south celestial poles, carrying the sun, moon and stars with it. To this the apparent daily course of the sun and moon is due. Their course seems to us oblique, as we are north of the equator.

If the earth’s axis were set vertically to the plane of its orbit round the sun, then it would follow that the plane of the equator would pass through the centre of the sun, and that the line drawn by the sun in its apparent revolution against the background of the celestial sphere would be in the same plane. That is, the sun would seem to move round a circle in the heavens in the same plane as the earth’s equator, or round the celestial equator. But the earth’s axis is inclined at 23½° to the plane of its orbit, and therefore the apparent path traced by the sun in the celestial sphere, which is the same path as the earth would really follow to an observer on the surface of the sun, is inclined at 23½° to the celestial equator. This is the ecliptic, and is really the line of the plane of the earth’s orbit extended to cut the celestial sphere.

4. The orbits of the moon and planets

All the planets move round the sun in orbits whose planes are slightly inclined to that of the earth, the plane of Mercury having the greatest inclination of 6°. The plane of the moon’s orbit round the earth is also inclined at 5° 9′ to the ecliptic. The orbits of the moon and all the planets must necessarily intersect the plane of the earth’s orbit on the ecliptic at two points, and these are called the nodes of the moon and each planet respectively. In consequence of the inclination being so slight, though the course of the moon and planets is not actually on the ecliptic, they are all so close to it that they are included in the belt of the zodiac. Thus the moon and all the planets follow almost the same apparent course on the zodiac or belt round the ecliptic in the changes of position resulting from their own and the earth’s orbital movements with reference to what are called the fixed stars.

5. The signs of the zodiac

As the sun completes his circuit of the ecliptic or zodiac in the course of a year, it followed that if his course could be measured and divided into periods, these periods would form divisions of time for the year. This was what the ancients did, and it is probable that the measurement and division of time was the primary object of the science of astronomy, as apart from the natural curiosity to ascertain the movements of the sun, moon and planets, when they were looked upon as divine beings controlling the world. They divided the zodiac or the path of the sun into twelve parts, and gave to each part the name of the principal constellation situated on, or adjacent to, that section of the line of the ecliptic. When they had done this and observed the dates of the sun’s entry into each sign or rāshi, as it is called in Hindi, they had divided the year into twelve solar months. The following are the Hindu names and meanings of the signs of the zodiac:

The signs of the zodiac were nearly the same among the Greeks, Egyptians, Persians, Babylonians and Indians. They are supposed to have originated in Chaldea or Babylonia, and the fact that the constellations are indicated by nearly the same symbols renders their common origin probable. It seems likely that the existing Hindu zodiac may have been adopted from the Greeks.

6. The Sankrānts

The solar year begins with the entrance of the sun into Mesha or Aries.²¹³ The day on which the sun passes into a new sign is called Sankrānt, and is to some extent observed as a holy day. But the Til Sankrānt or entry of the sun into Makara or Capricorn, which falls about the 15th January, is a special festival, because it marks approximately the commencement of the sun’s northern progress and the lengthening of the days, as Christmas roughly does with us. On this day every Hindu who is able bathes in a sacred river at the hour indicated by the Joshis of the sun’s entrance into the sign. Presents of til or sesamum are given to the Joshi, owing to which the day is called Til Sankrānt. People also sometimes give presents to each other.

7. The nakshatras or constellations of the moon’s path

The Sankrānts do not mark the commencement of the Hindu months, which are still lunar and are adjusted to the solar year by intercalation. It is probable that long before they were able to measure the sun’s progress along the ecliptic the ancients had observed that of the moon, which it was much easier to do, as she is seen among the stars at night. Similarly there is little reason to doubt that the first division of time was the lunar month, which can be remarked by every one. Ancient astronomers measured the progress of the moon’s path along the ecliptic and divided it into twenty-seven sections, each of which represented roughly a day’s march. Each section was distinguished by a group of stars either on the ecliptic or so near it, either in the northern or southern hemisphere, as to be occultated by the moon or capable of being in conjunction with it or the planets. These constellations are called nakshatras. Naturally, some of these constellations are the same as those subsequently chosen to mark the sun’s path or the signs of the zodiac. In some cases a zodiacal constellation is divided into two nakshatras. Like the signs, the nakshatras were held to represent animals or natural objects. The following is a list of them with their corresponding stars, and the object which each was supposed to represent:²¹⁴

8. The revolution of the moon

All the zodiacal constellations are thus included in the nakshatras except Capricorn, for which Aquila and Delphinis are substituted. These, as well as Hydra, are a considerable distance from the ecliptic, but may perhaps be nearer the moon’s path, which, as already seen, slightly diverges from it. But this point has not been ascertained by me. The moon completes the circuit of the heavens in its orbit round the earth in a little less than a lunar month or 27 days 8 hours. As twenty-seven nakshatras were demarcated, it seems clear that a nakshatra was meant to represent the distance travelled by the moon in a day. Subsequently a twenty-eighth small nakshatra was formed called Abhijit, out of Uttarāshādha and Sravana, and this may have been meant to represent the fractional part of the day. The days of the lunar month have each, as a matter of fact, a nakshatra allotted to them, which is recorded in all Hindu almanacs, and enters largely into the Joshi’s astrological calculations. It may have been the case that prior to the naming of the days of the week, the days of the lunar month were distinguished by the names of their nakshatras, but this could only have been among the learned. For though there was a nakshatra for every day of the moon’s path round the ecliptic, the same days in successive months could not have the same nakshatras on account of what is called the synodical revolution of the moon. The light of the moon comes from the sun, and we see only that part of it which is illuminated by the sun. When the moon is between the earth and the sun, the light hemisphere is invisible to us, and there is no moon. When the moon is on the opposite side of the earth to the sun we see the whole of the illuminated hemisphere, and it is full moon. Thus in the time between one new moon and the next, the moon must proceed from its position between the earth and the sun to the same position again, and to do this it has to go somewhat more than once round the ecliptic, as is shown by the following figure.²¹⁵

Fig. 2.—Revolution of the Moon round the Earth.

9. The days of the week

As during the moon’s circuit of the earth, the earth is also travelling on its orbit, the moon will not be between the earth and the sun again on completion of its orbit, but will have to traverse the further arc shown in the figure to come between the earth and the sun. When the moon has completed the circle of the ecliptic from the position ME, its position relative to the earth has become as NF and it has not yet come between the earth and the sun. Hence while the moon completes the circuit of the ecliptic²¹⁶ in 27 days 8 hours, the time from one new moon to another is 29 days 13 hours. Hence the nakshatras will not fall on the same days in successive lunar months, and would not be suitable as names for the days. It seems that, recognising this, the ancient astronomers had to find other names. They had the lunar fortnights of 14 or 15 days from new to full and full to new moon. Hence apparently they hit on the plan of dividing these into half and regulating the influence which the sun, moon and planets were believed to exercise over events in the world by allotting one day to each of them. They knew of five planets besides the sun and moon, and by giving a day to each of them the seven-day week was formed. The term planet signifies a wanderer, and it thus perhaps seemed suitable that they should give their names to the days which would revolve endlessly in a cycle, as they themselves did in the heavens. The names of the days are:

The termination vāra means a day. The weekdays were similarly named in Rome and other countries speaking Aryan languages, and they are readily recognised in French. In English three days are named after the sun, moon and Saturn, but four, Tuesday, Wednesday, Thursday and Friday, are called after Scandinavian deities, the last three being Woden or Odin, Thor and Freya. I do not know whether these were identified with the planets. It is supposed that the Hindus obtained the seven-day week from the Greeks.²¹⁷

10. The lunar year

Four seven-day weeks were within a day and a fraction of the lunar month, which was the nearest that could be got. The first method of measuring the year would be by twelve lunar months, which would bring it back nearly to the same period. But as the lunar month is 29 days 13 hours, twelve months would be 354 days 12 hours, or nearly eleven days less than the tropical solar year. Hence if the lunar year was retained the months would move back round the year by about eleven days annually. This is what actually happens in the Muhammadan calendar where the twelve lunar months have been retained and the Muharram and other festivals come earlier every year by about eleven days.

11. Intercalary months

In order to reconcile the lunar and solar years the Hindus hit upon an ingenious device. It was ordained that any month in which the sun did not enter a new sign of the zodiac would not count and would be followed by another month of the same name. Thus in the month of Chait the sun must enter the sign Mesha or Aries. If he does not enter it during the lunar month there will be an intercalary Chait, followed by the proper month of the same name during which the sun will enter Mesha.²¹⁸ Such an intercalary month is called Adhika. An intercalary month, obtained by having two successive lunar months of the same name, occurs approximately once in three years, and by this means the reckoning by twelve lunar months is adjusted to the solar year. On the other hand, the sun very occasionally passes two Sankrānts or enters into two fresh signs during the lunar month. This is rendered possible by the fact that the time occupied by the sun in passing through different signs of the zodiac varies to some extent. It is said that the zodiac was divided into twelve equal signs of 30° each or 1° for each day, as at this period it was considered that the year was 360 days.²¹⁹ Possibly in adjusting the signs to 365 odd days some alterations may have been made in their length, or errors discovered. At any rate, whatever may be the reason, the length of the sun’s periods in the signs, or of the solar months, varies from 31 days 14 hours to 29 days 8 hours. Three of the months are less than the lunar month, and hence it is possible that two Sankrānts or passages of the sun into a fresh sign may occasionally occur in the same lunar month. When this happens, following the same rule as before, the month to which the second Sankrānt properly belongs, that is the one following that in which two Sankrānts occur, is called a Kshaya or eliminated month and is omitted from the calendar. Intercalary months occur generally in the 3rd, 5th, 8th, 11th, 14th, 16th and 18th years of a cycle of nineteen years, or seven times in nineteen years. It is found that in each successive cycle only one or two months are changed, so that the same month remains intercalary for several cycles of nineteen years and then gives way generally to one of the months preceding and rarely to the following month. Suppressed months occur at intervals varying from 19 to 141 years, and in a year when a suppressed month occurs there must always be one intercalary month and not infrequently there are two.²²⁰

This method of adjusting the solar and lunar years, though clumsy, is so far scientific that the solar and lunar years are made to agree without any artificial intercalation of days. It has, however, the great disadvantages of the frequent intercalary month, and also of the fact that the lunar months begin on different dates in the English solar calendar, varying by nearly twenty days.

12. Superstitions about numbers

It seems not improbable that the unlucky character of the number thirteen may have arisen from its being the number of the intercalary month. Though the special superstition against sitting down thirteen to a meal is, no doubt, associated particularly with the Last Supper, the number is generally unlucky as a date and in other connections. And this is not only the case in Europe, but the Hindus, Persians and Pārsis also consider thirteen an unlucky number; and the Muhammadans account for a similar superstition by saying that Muhammad was ill for the first thirteen days of the month Safar. Twelve, as being the number of the months in the lunar and solar years, is an auspicious number; thirteen would be one extra, and as being the intercalary month would be here this year and missing next year. Hence it might be supposed that one of thirteen persons met together would be gone at their next meeting like the month. Similarly, the auspicious character of the number seven may be due to its being the total of the sun, moon and five planets, and of the days of the week named after them. And the number three may have been invested with mystic significance as representing the sun, moon and earth. In the Hindu Trinity Vishnu and Siva are the sun and moon, and Brahma, who created the earth, and has since remained quiescent, may have been the personified representative of the earth itself.

13. The Hindu months

The names of the Hindu months were selected from among those of the nakshatras, every second or third being taken and the most important constellations apparently chosen. The following statement shows the current names for the months, the nakshatras from which they are derived, and the constellations they represent:

Thus if the Pleiades are reckoned as part of Taurus,²²¹ eight zodiacal signs give their names to months as well as Orion, Pegasus and Aquila, while two months are included in Leo. It appears that in former times the year began with Pūs or December, as the month Mārgashīr was also called Aghan or Agrahana, or ‘That which went before,’ that is the month before the new year. But the renewal of vegetation in the spring has exercised a very powerful effect on the primitive mind, being marked by the Holi festival in India, corresponding to the Carnival in Europe. The vernal equinox was thus perhaps selected as the most important occasion and the best date for beginning the new year, which now commences in northern India with the new moon of Chait, immediately following the Holi festival, when the sun is in the sign of Mesha or Aries. At first the months appear to have travelled round the year, but subsequently they were fixed by ordaining that the month of Chait should begin with the new moon during the course of which the sun entered the sign Aries.²²² The constellation Chitra, from which the sign is named, is nearly opposite to this in the zodiac, as shown by the above figure.²²³

Fig. 3.—The Hindu Ecliptic showing the relative position of Zodiacal Signs and Nakshatras.

Consequently, the full moon, being nearly opposite the sun on the ecliptic, would be in the sign Chitra or near it. In southern India the months begin with the full moon, but in northern India with the new moon; it seems possible that the months were called after the nakshatra, of the full moon to distinguish them from the solar months which would be called after the sign of the zodiac in which the sun was. But no authoritative explanation seems to be available. Similarly, the nakshatras after which the other months are named, fall nearly opposite to them at the new moon, while the full moon would be in or near them.