 So, I think the last one is introduction of telescopic astronomy and some important remarks. Now, I will not discuss telescope here because that is not the objective and I hope that most of you are aware of the basic principles behind optical telescope both reflecting type and reflecting type. Now, how it was developed by Galileo under what circumstances that is a wonderful story and I give a lecture on that and a drama has been written which will be staged in Calcutta and Bhopal. That story of Galileo is generally not known. It is only the fight with the charge, etc., inquisition. That is the main thing of the drama popularly. But this one I prepared during the summer and now rehearsals are going on. Maybe sometimes I will request IIT Kanpur, Jim Khanna to stage it, you know. You identify a person for Galileo's role. So what I will do today is that introduction of telescopic astronomy in India briefly and some interesting stories behind it and another thing I will tell you that it came primarily for observing the transit of Venus. You might have heard about it recently in 2012. We had the transit of Venus, is not it? Was there any observation in the campus? You have an astronomy club because these transits are very important because that helps you to determine the distance of the earth, sun, etc., very accurately. So it has always been an important task and it is not a very frequent event. Now I think the next one will be about some hundred years back later. So in one lifetime one can see at the most two such transits. So I think in India the first telescope came along with the Jesuit priests and if you remember in the very first lecture I mentioned that in Thailand French government king of France sent a team at the request of the king of Thailand and they came with a telescope and some astronomers in the 16th century or 17th century then there was a coup and they had to leave and they fled to India and settle in Pondicherry with their telescope. But even before that the first Jesuit priests came and they colonized Goa in the 16th century, beginning of the 16th century and then I think in 1541 Saint Francis Xavier came to Goa and the mission was established if you have read that. Even Akbar came to know about the scholarship of these Jesuit priests and he invited some missionaries to his court and Father Antony I do not know how to pronounce it in French must be something different as it looks like the French pronunciation is very different from what you write I do not know why. Had it been German I would have read it and he was in the group that visited Akbar's court and could make a very good impression on the emperor with his knowledge of science and astronomy. When Akbar took him along with to Kabul in 1580 he actually determined the positions of about 100 places while traveling from Agra to Kabuhi and he also compiled a partial map of India that was based upon his astronomical observations. Now Jai Singh we have discussed in the last lecture the it was of course he was a medieval astronomer and dealt with only this Siddhantik or Jiji astronomy considering a geoscientific model and most historians of science considered Jai Singh to be a historical anachronism and his contributions as scientifically irrelevant. It is not commonly known that he made use of his telescope which he had and carried out some observations. It must be remembered as mentioned earlier it took quite some time for astronomical telescope to become instruments for observation when these cross cross where technology was found out it is not a technology but the device kind of thing. So it took quite some time for astronomical telescope to become instruments and earlier it was only for viewing kind of thing qualitative results you could get and the results which we could get from the heliocentric model and those early telescopes were no way better actually you could see that even one minute of arc you could do two minutes of arc with the help of naked eye instruments. So there was no motivation on the part of Jai Singh to pay too much effort and attention to telescopic observations or the heliocentric. According to scholars like S.M. Ansari Jai Singh actually did something and references are found on the following topics in his writings that means the ellipticity of the lunar and solar orbits he worked on that the existence of four Jovian satellites obloid shape of planet Saturn as I mentioned in the last class and phases of planet Venus and Mercury. Now a detailed study of several available manuscripts of G.G. Mohammed Shah which was compiled by Jai Singh have been analyzed in depth by Ansari before coming to the above conclusion. Now as Jai Singh continued with the idea of a geocentric universe researchers failed to notice many interesting diagrams and noting in the margin of the manuscript which indicate telescopic observation not in the main text but in the margins there are lots of notings. Another thing I mentioned that why Jai Singh really could not go into the heliocentric model because he depended too much on the Jaiswi priests and he sent them to Portugal and the Jaiswi priests they themselves were very much against the heliocentric model and they did everything possible to isolate Jai Singh from the new developments in Italy and Europe. Anyhow but the main impetus for astronomical activities by Europeans in the early period was predominantly of scientific inquisitiveness and another thing that is India being a tropical country with frequent occurrence of clear sky and warm weather provided better conditions for astronomical observations for the people from France and England. The other source of importance of astronomy in India was from a practical requirement for the newly established colony to survey and map India. Though the Europeans reached India through sea routes even before the Mughals came actually they remained confined to the coastal areas only. So their knowledge about the interior of the subcontinent it was negligible the peninsula of India was not known to them and in those periods the subject astronomy had two wings pure astronomy and applied astronomy. Pure astronomy represented the field involving the basics of astronomical science whereas applied astronomy was primarily for surveying purpose. You know astronomy was the very important tool for surveying the land and the initial major application of astronomy in India, telescopic astronomy in India was for surveying purpose. One was for determination of the latitude other was determination of longitude and determination of longitude was with the help of transit telescope. They are very special telescopes you will find I have given in the book and these telescopes had very limited maneuverability but gave much accurate results. They were used for the longitude determination. Latitude determination was somewhat easier and Father Giovanni Bouch started observation related to the survey of the country in the year 1689 at Pondicherry. You know the great triangular survey of India is a very famous I think I don't know whether our library had that book many things happened finding the height of the peaks like Everest etc all it was a very great activity in the history of civil engineering and surveying great trigonometrical survey of India and it started from south the first one what we say the backbone was created and then it sprayed on both sides by triangulation. Now his map of the interior was the first dependable map in the year 1722. That's one curious question from that positional astronomy from the different timings like when others are or from the difference in sun's shadow when you get the longitude as well longitude by the sun. Oh then you actually you know for longitude you need a clock earlier the problem of longitude there is a book, book's type name itself is longitude you know when Galileo gave the first hint that you can use the four moons of Jupiter which are visible from any place and their occultation can be used which is a periodic event which could be used as a clock and it was being done and when it was being done wemer was one of the person who was trying to do that and he had a byproduct the speed of light because you have all read in history of science that he found first the history of light a velocity of light and that was on that occasion it was trying to use the moons of Jupiter as a clock. So he got the speed of light and 1687 as I mean this is that story I will not repeat and those people they brought that 12 foot telescope 12 foot not 12 inch 12 foot telescope and they started pure astronomical observation from Pundicherry the main contributions were observing the comet of December 1689 discovery of the binary nature of Alpha Centuries then correct latitude and longitude of Pundicherry the Megalith clouds and correct prediction of the lunar eclipse of April 14 1689. Apart from making astronomical observations the father started teaching astronomy at a Jesuit school in Myla food till the end of his life in 1693. More organized activities started subsequently for both pure astronomy and for the major surveying work by East India Company and major source of inspiration for astronomical observation was impending transit of Venus in 1761 and 1769. This transit of Venus occurs at interval of 8 years then it will take another 100 years you have to wait for the next one. That was the main thing and at that time during this period England and France they were at war a 7 year war was going on when this was to happen. So both government sent the teams to India and there is a very nice story and about this. So this story I will tell then I will explain about the how it is used. This story is very interesting story in the history of science and it is also a tragic thing. I will read it is a story it is just like a story you see how sometimes fate can be so cruel to scientists. It should be remembered that when the first of these transits took place in 1761 Europe's 7 year war was raising from 1756 to 1763. Both the British and French scientists were planning the observation at different places from where the transit was expected to be visible. The British team which headed to Sumatra had to make their observation at Cape of Good Hope because of bad weather the ship had lot of difficulties and so they were forced to do it from Cape of Good Hope and the results were not at all acceptable because it was a moving ship. The French team went to Siberia on an island in the Indian and an island in the because you need to have the observation from two different latitudes almost along a same meridian approximately. I will explain the whole thing then you will realize why. It is essential to observe and take the data from two different latitudes of the transit phenomena. The astronomer in charge of the team to India was a large entail whom I mentioned in the lecture. And large entail after arriving near the Malawar coast came to know that the French colonial punditry that was his destination was taken over by the British. So he had to turn back towards Mauritius which was under French control and observed the transit on 6th June from a moving ship with great difficulty. So large entail decided to observe the next transit on 4th June 1769. So this was 1761. So the next one was after 8 years. So he decided not to go back to Beirut to wait and observe the next one. So he stayed and waited at Mauritius for the next 7 years and arrived at Punditry on 27th March 1768 to observe that 4th June transit almost a year in advance. And a suitable observatory was erected at Punditry with the help of the local French government. And interestingly the British at Madras also helped large entail by providing him a very good telescope for the observation. By that time the war was over in Europe. So during the year large entail spent at Punditry he came across some Siddhantic astronomers as I mentioned that Nana Moodu and other that story who could do the calculation using a table. But the anti-mime climax of the story is that large entail's long wait and 11 year long voyage to India was that on the day of the event in June 1769 the sky was over Punditry covered with clouds and the mission to observe two transits of Venus remained unaccompanied. So 11 years effort nothing happened. It is a really painful thing. Now I think the observation now I will say this was an interesting story how scientists devote their life ultimately sometimes they may not be rewarded with good results. Now the planet Venus and Mercury's orbit are within that of the earth and obviously therefore you will see at times they are crossing through the disk of the sun and that is called the transit. And they are found to move across the sun's disk because they are very small besides being fascinating phenomena in solar astronomy these transits were of great importance to early telescopic astronomy for accurate determination of the earth's sun distance. As the angular diameter of Venus during a transit is about 1 minute of heart compared to 31.5 minutes of heart of the sun's disk it appears as a small dark dot against the disk of the sun. Lot of people in Calcutta they arranged observation of the transit of Venus. I wonder why it was not done here. Many group, student groups and researchers they did it. They went to different places and they did it. But of course I must tell you that observing it from just one place may not give you that good results. So generally sometimes they do it from two places through different lectures. Now there are about 12 transits of Venus in every millennium that when in 1000 years you will get only 12 opportunities to observe Venus transit. That is why they are so important. And the transits take place in pairs 8 years apart followed by another pair after 121.5 years. So 2012 we had one. So the next one will be 2133. So in the last year your grand-grand sons can observe that of course. In the last 4 centuries the transit of Venus occurred as per the table given below. You can see which were observed actually. 1631, 1639 in December, 1761, 1769 in June. That is why it is difficult because in June in India generally you will have cloud cover whereas December is a good one. But in winter it rains. The return monsoon. Then 1874, 1882 and the last one was 2004 and 2012. So now I think we have lost the opportunity. None of us will be able to see the next one. This is transit of Venus is like this. So this is the sun. This is the orbit of Venus and this is the orbit of the earth. So from earth, from two places you observe the transit. So what happens? Venus describes an earth or a line in this disc of the sun as seen from the earth. But the two lines are different because one draws a line here and these draws a line there. And these two lines their gap is nothing but the parallax of Venus at sun. So the one which I think was observed from Pretoria and London simultaneously the two lines which were seen, path of Venus during the transit. This is seen from Pretoria that is South Africa and this is observed from London. These are the two lines which were described and found. So you see the distance to the sun from the earth and R be the earth's radius. Then the solar parallax P when observed from equator and from the pole that means the distance is R. So parallax will be R by D. Simple. And P is nothing but angle in radiance. Or the distance you can find out. If you can find out the parallax then distance you can find out as R by P. Now if delta be the angular distance between the two paths just now I shown you traced by Venus as observed from two different locations on the earth at distance of s apart in a direction perpendicular to Venus's path of course. Then the parallax which you will get in this case is nothing but delta and D by minus 1 is simple geometry and where D is the distance of Venus from the sun and using Kepler's third law we know that the radius of the earth orbit and radius of the Venus orbit their ratios Q is square of the periods ratio. You all know that that is Kepler's third law. So what they do they apply that then. So now you get another relation capital D by small D distance of the earth from sun by distance of Venus from sun that Q is the period is known accurately. So in all such measurements distance is the most difficult thing to measure. Period you can measure angle you can measure I mean to say angular distance. So you can figure out the two ratios the distance of the earth and distance of the Venus from sun that is 1.38248. So when small p is 0.38248 delta and capital D is s by 0.38 that this ratio if D by D is this much minus 1 means what it will be 0.38248 into delta. So this is nothing but this you subtract 1 and capital D will be then also s divided by this that is the parallax. So this is the typically the procedure very simple procedure and the observation of 1761 Venus transit from India it resulted in inaccurate and varying values of the solar parallax. However a re-analysis of all the observational data led to a mean value of 8.56 seconds apart. So the distance which I showed you it is not it was about 5 and half seconds apart. So this was one of the primary motivation to bring telescope in India observing the Venus transit and both info scientist they did it. And another important motivation was the survey of India as I was mentioning. Now till the 18th century the maps of the subcontinent were based upon the information contained you know Ptolemy gives a detailed description of course inaccurate about the Indian peninsular you know that is something very surprising. So old text by Ptolemy Ulugbek and Aini Akwari these were the source from which the maps of India used to be drawn and obviously they are very inaccurate and East India company after gaining political control over a large part of the subcontinent started mapping to gain knowledge of the interiors and coastal areas for their further plans to expand their kingdom. So the noted astronomer Ruben Baro was the first to suggest the use of astronomy for surveying and mapping India. And he also conducted extensive astronomical observations for accurate determination of latitudes and longitudes these are the two primary requirements and thus the detailed surveying of the subcontinent led to the development of telescopic astronomy in the year 1786. Some reorganizations and etc the setup was ready and 1792 considered to be the official year and this was done in Madras. In India the first observatory it was a very ram cycle affair of course a small building the pictures of those I have given in the book you know. So it was a small building with some small outfit that was the first observatory 1786 initially it was semi-government some private enterprise kind of thing but a formally accepted government observatory it became 1792 and this is also considered to be the official year of the establishment and Goldingham was the first in charge astronomer of that first observatory in India in 1792. Now subsequently observatories both private and government owned were set up at Lucknow, Trivandrum, Pune, Deradun, Calcutta, Kodaykanal, Hyderabad and Bhajjar. The universities also established observational facilities at Calcutta, Elawa the University and B.H.U. Work on physical astronomy also started that was of course a bit later and in solar astronomy India made an impressive contribution because Evershade was the astronomer in charge of Kodaykanal observatory for a long time and these considered to be one of the most noted astronomer for solar astronomy and his data are still used and kept in Kodaykanal. Now some important things should be known to you at this time. So I told about Madras Observatory. This Madras Observatory from the beginning of 19th century its major usage was related to great trigonometric survey of India and Madras became the Greenwich of India. The till 1830 this observatory was engaged in surveying organized astronomical finding oriented astronomy because of the ongoing survey of India and subsequently this observatory made many important contributions including the publication of the famous Madras catalog of 11,000 stars in the southern sky in the year 1843. From this observatory Captain Jacob showed that the recently discovered ring of Saturn was not solid and after 1864 this observatory did not receive any new instrument and the most productive period for this observatory was 1830 to 1864. The first Indian astronomer who was associated with Madras Observatory in the 19th century was Chintamani Raghunathacharya. He was the head assistant and a skill observer. His first paper was submitted to the Royal Astronomical Society in 1859 and he was the first Indian to have discovered two new variable stars. In 1872 he was elected as a fellow of the Royal Astronomical Society the first one. Now the government of India decided to set up an observatory at Kodai canal which still one of the major observatory of India and which had the objective of making solar observations as I mentioned as solar activities why they were interested in solar observatory because India being a tropical country it was expected that solar activity will be controlling our monsoon which is so important for the agriculture in India that's why they decided to establish Kodai canal observatory primarily for solar observation. Also something like that was done in Deraghun and Lakram and Trivandam observatories there is 240 funny story. The progress of Madras Observatory and great trigonometric survey prompted two native kings one in the north and the other in the south to promote astronomical observations. Now truly speaking they did so to assist the British because in those days many things they used to do to assist and help them to get all kinds of other things like like Ketab like Raibahadur this show somebody will make a rescue or somebody will make a hall for ball dance all kinds of things so they did this to primarily assist. The Nava of Oath declared independence from the Ailing mobile empire in 1819 and his successor Nasibuddin Hyder founded an observatory at Lucknow in the year 1831. It is interesting if somebody does research to trace where it was and what kind of remnants are still available nobody has won it so far. However he requested the British to appoint a director for the observatory and the major James Dowling Herbert was appointed as the incumbent receiving generous funding from the King Herbert ordered for the best possible instruments. Unfortunately he died in 1833 just after two years and the next astronomer in charge was Lieutenant Colonel Richard Wilcox who was also an astronomical assistant at the great trigonometric survey. He built the observatory and the instruments were put up and he planned the observational activity quite nicely. Finally the observatory was ready for regular observation in 1841. Since it contained the best possible instruments including a Mural Quadrant this Mural Quadrant you will find if you see Taipuba his pictures etc. This Quadrant was a very favorite instrument for angular measurement bigger the Quadrant more accurate the marking and bigger better the result. A Mural Quadrant a transit telescope as I mentioned transit telescopes could rotate only like that and their objective was primarily to see when a particular star just process the genetic that time. Since it contained and an equatorial telescope and clocks because clock was very important so you will find that every old astronomical observatory so clock will be mentioned because that is so important. And also there was hope for producing excellent results but unfortunately the results from the observations were never published and after Wilcox died in 1848 the King closed down the observatory on the ground of its not being useful to the people about. The British wanted to rebuild it after the mutiny of 1857 but it was found to have been destroyed by the rebel soldiers and the records containing all the results were also eaten by insects and thus one of the best equipped astronomical observatories in India was closed down without producing any result. The initiative for setting up the Trivandam Observatory was taken up by the British scientist and King Raja Bharma happily approved the request and John Caldecott was the main person when the observatory was established in 1837. They were more or less same time they out and this one. The observatory was also furnished with transit telescope, morale circle, equatorial telescope and clocks. Unfortunately this observatory also made with the same fate as that of the counterpart in Lucknow. By 1852 the instruments were so dilapidated that the astronomical observation came to an end and luckily Trivandam being located near the magnetic equator the observatory sustained some scientific work on magnetism and meteorology. More or less during the same period then I think I went on a Pune there was an observatory and some observatories were erected on private enterprise in those days. So Pune Observatory there is an interesting story there are the observatory then observatories in Calcutta then this is a private observatory very well known Takta Singhji Observatory Pune. So after this solar observatory at Deradum another solar observatory came up in Pune in 1888. The single person behind the setting above this first modern astrophysical observatory was Kavashji Dadabhai Naganwala. He was born in the year 1857 and was a brilliant student of physics at Elfinstone College Bombay. He received the Chancellor's gold medal in his MA examination in 1878. Subsequently he joined the college as a lecturer in physics 1882. In the same year when Maharaja Takta Singhji of Havanagar visited the college he appealed to the Maharaja for a donation to start a spectroscopic laboratory. You can see now spectroscopic activities started. The grant of his 5000 was matched by a similar amount and after the discovery of solar spectral lines by a farmer for around 1812 and subsequent work by Kershwap and Boonsen in 1859 this spectroscopy started being used to the celestial bodies. In India Father Lafont I think many Amitabha you may have heard about Father Lafont. You are a professor at Saint Xavier's College and at the same time Swami Vivekananda Lafont they are very close collaborators and Lafont was one of the major persons to promote science education in India and Mohendlal Sarkar Lafont they used to organize scientific lectures as RIT Kanpur does evening like this. The ticket used to be rupees 2 in the beginning of the 10th, 20th century and you know most often the hall used to be full without any seat many vacant. Now if you organize a lecture in Calcutta if you give people 200 rupees you may get a few but you see the how the society deteriorates. Anyhow so the Saint Xavier's College also had an observatory Calcutta. When you were students it was there so Father Gore used to be the primary person. Now the Saint Xavier's College observatory Nagamwala visited and he was so impressed and gained experience in the spectroscopy and at Lafont's recommendation Nagamwala proceeded to Europe in 1884 to finalize the equipments he wanted to have. Then of course he changed his area he became an astronomer and he came back and started the astronomical observatory in Pune. Of course later it had to be because all such single person endeavors they made with unfortunate situation that after their death nobody was there to take up. So what happened all the equipment of this were transferred to Kodaikanal. Kodaikanal observatory is still one of our primary observatories and I think it is under the control of Indian Institute of Astrophysics at Koramangala Bangalore. Then there was another private entrepreneurship in Hyderabad Nizamiya Observatory. It didn't produce much good result but it made some very good star catalogues. It was the special effort they had and this work which they started and I think 7,63,540 2 stars observatory and result was published in 12 volumes. Then there was another very private observatory in Vizag Jaggarhav and Narasimha the Fatharin Law and Sunin Law they set up something which of course vanished after some time and in West Bengal or not West Bengal, Bengal this Kalinath Mukherjee and Radha Vindachandra were some early astronomers and what happened Kalinath Mukherjee was born at Jaijia in Jesho district which is now in Bangladesh and received his college education at Krishnanagar and graduated with honors in mathematics, philosophy and Sanskrit. After graduating in 1872 he studied law and 1873 he started practicing law at his native district. During his college education at Krishnanagar he came in contact with Sir M. J. Harchel the grandson of the great astronomer Sir William Harchel you know Harchel he discovered which one, Uranus or planets? I think Uranus or Neptune which one? I forget which is called Harchel's planet so I think he also made lot of observations and he wrote the Sanskrit text also Bhagola Chitram Radha Vindachandra was also a private astronomer in Bengal and ultimately the main impetus to astronomy in India came from Prof. Vainu Bakut. You must have heard is that he is the primary person in promoting astronomy. He first came to Lahavata Observatory which was shifted to Nainita which is still there now they have changed the name to Aryavatar Research Institute for Observational Science at Manura peak but later he shifted to Kodaikanal and spent his life and the main big telescope was his design the largest telescope we had till recently. Now of course we have bigger one but he unfortunately died at a young age but he is that telescope and observatory has been named after him as Vainu Bakut Observatory. Then of course any of these people like Gavunathachary, Kalyan and Tukar ji they also did astronomy because a lot of astronomy was seen. No I think they did astronomy only. Primarily star catalogs, observations, finding out double stars or variable stars these are the kind of things. They were not astro-waters. Tycho Bhair was a big astro-water. Even Kepler was an astro-water. Kepler earned his livelihood just because he was the king. They told the king that you should do these. They know you win the war on that kind of thing. Most of the people they are nobody was interested in what is happening whether earth is going down the sun or sun going down the earth. It hardly matters to me. Even today also I believe you don't really bother but I think their main thing was astrology but the only good thing is that it provided the motivation to do astronomy and the science progressed. Now I think of the last two topics I wanted to take. One will be antiquity of Indian astronomy and the other will be originality of the Indian astronomy. Both are actually little bit controversial issues because there are two camps. One camp will say it is Indian astronomy is very recent. They are all copied from the Hellenistic astronomy in Greek and 11th century AD etc. Another group will say they are very original and long back they have the originality and they are very old. So I think it is better to have some discussion and primarily keeping the scientific aspect of the whole thing rather than depending being emotional that everything you push back to very antiquity and millions of years ago I think that is not a good thing. And that's why we have always lost credibility in the western science because there will be always a group of people who will say these are all tens of thousands of years, lakhs of years. But as I mentioned personally I think though I have not found it anywhere that this kind of idea came mainly because of that calculation procedure. Mohajugo these people really started thinking they are real physical things like Mohajugo Akali. Now I think archaeoastronomy is a very interesting topic. Nowadays planetarium softwares are there and as you have done anybody can download and can do little bit of study. Though you cannot do research with the simple softwares for that you need some more elaborate softwares. But I think many things you can study. So this archaeoastronomy is a new kind of subject. Now it has two branches in one branch of archaeoastronomy you look into the orientation of very ancient structures say like say pyramid or Harappa Manjida or settlements because it has been found even in ancient times the major structures the people used to orient with some important principal directions like north, south, east ways like that. They will not put it at random. So like pyramids etc. they are very accurately oriented towards northeast of that time. So then seeing the present day orientation the deviation from the two directions you can find out approximately how many years or thousand years back the directions which was used could be the two directions of north or east. That is one for that you need a big structure. Another branch of archaeoastronomy there you do not need any structure or anything you only need a description. And by now I am quite sure you have an idea what the description is. It is the precision of the equinox but there are quite a few things which can be done one is the precision of the equinox and another is the advance of the perihelion. Both are useful in archaeoastronomy. So in the precision of the equinox where our axis precesses is a period of 25,800 years long enough period to span the whole human history and what are actually seen the constellations in different seasons see like as I mentioned that now in winter if you stand in the evening you will find Orion is rising in the sun sky but if you find a description that Orion is rising in the springtime then obviously it was much earlier sometime. Another is the asterisms that is nakshatras and stars as solstitial and equinoctial positions that in which nakshatra was in the equinox this was very important as you will see later when I come to the application that and that was that mentions are there and that changes because of the precision of the equinox what is on varnal equinox today after 5000 years should not be there because the varnal equinoctial point will shift along the ecliptic to a different position so different nakshatra will be in the equinox third is description of heliacal rising heliacal rising I have explained that what stars you find last to rise before the sunlight appears and that was very common in India because our moonies they used to get up very early not like our students and our children at 10 o'clock you have to push them up so they used to go take bath and they used to pray all those things facing east always of course in India early morning it is always you pray facing east and obviously you will observe things if you do it again and again day after day, year after year you will observe if you are observing and also analysis of the pole star as I mentioned the pole star changes with time today we have a pole star which is called polaris and 15 or 2000 years back there was no pole star and maybe again 3500 years back there was another pole star so that also gives some idea of giving approximate it cannot make any accurate calculation but can give you some idea about the antiquity of things and another one which one tries is the analysis of the ancient eclipses there will be always some description particularly total solar eclipse is a very very noticeable event and in all text you will find that suddenly in the daylight it becomes dark there always there will be pictures for describing it you know and now you know that if you analyze those eclipses you can try to find out when it happened because the location when it happened which particular season, date it happened, which particular time of the day as I think who was telling many people tries to interpret jayad dhat bath where some disappear then came out again as a total or near total solar eclipse before sunset you know so people have used that and tried to use software and find out that whether or when such a solar eclipse took place but difficulty as I was mentioning that eclipse particularly total eclipse is only visible from a small area on the surface of the earth and the so location of the earth surface particular orientation is very important when you go back thousands of years back it is very difficult because rotational history of the earth it is slowing down you know it is approximately I think 6 into 10 raise to minus 22 radian per second square is our retardation but that is an average value there are fluctuations so this secular mean value may not give you correct location of the earth surface so sometimes it does not match so therefore different software give different results about this eclipse another thing which is used rarity of event the two consecutive eclipses so in maharatha you will find that there were two eclipses within a fortnight as a 13 days gap that was considered to be very bad woman it is very clearly mentioned in the Uddhok Parbhava I believe so that also people have used software and they tried to see that when two consecutive eclipses took place within 13 days which is very rare again they have found something but it is not very easy particularly this eclipse during maharatha war results don't match different software give different results so therefore this can give sometimes some idea but not very dependable in my opinion my opinion is that precision of the equinox is the best and most stable and dependable way now advance of perihelion advance of perihelion is used in two ways one is important exaltation of mass this is a purely astrological terminology but the phenomena is not astrological what happens that masses orbit is elliptic earth orbit is also elliptic but ellipticity or eccentricity is very small so when mass is in opposition opposition means what that sun earth mass there is one line so mass will be nearest to earth now that becomes still more pronounced when masses are the perihelion position nearest to sun so therefore there are rare occasions when the masses are perihelion and also in opposition so that is the time when mass is nearest to earth and at that time the brightness of mass is three times that of star Sirius which is the brightest star and that is very visible in red star so bright that's what they call as exaltation of mass and there are reference to such exaltation of mass in the past and that also gives you because I will show you the calculation because the earth's rotation of the or advance of perihelion is 0.332856 degrees per century and for mass the advance of perihelion is 0.43355 degree per century now you see first let us see that if you try to apply earth to astronomy what results you get now I will not go into all kinds of that about the 2 eclipse say within the period of 13 I will not go into that there was another total solar eclipse at the time of death of Krishna which was 28 years after Mahavarta war that also sometimes we will see and it was visible in Dwarka you see that one which is most I will say nonambiguous was the death of Nisha it is very clearly mentioned that he died on the winter solstice day when the whole thing changed from Dakshinayan to Uttarayana he wanted to die on Uttarayana so he died on the winter solstice day and it was also mentioned that it was the 8th day on the brighter half of the month of Maha so Shuklasthami in month of Maha now you see if you use this terminology month of Maha means the full moon should be on Maha nakshatra so the configuration of the situation will be earth here Maha nakshatra this is the moon and Maha nakshatra in this direction so therefore in this situation you will see the full moon in Maha nakshatra and it happened not on the full moon day winter solstice was 7 days before so earth was somewhere here actually not here so this gap is 7 days by calculation you can see that on 2400 BC full moon took place at Maha nakshatra also on the winter solstice day just I think I will try to show you using that same actually you can do all these things study yourself now let us see 2400 BC how was the situation and now you are familiar how to get it so 2400 BC will be 2400 and winter solstice day let us see it will be same thing it will not matter much month of I think I will put it January or February let us see so we apply so I think let us see winter solstice day will be when sun is at the extreme end of the ecliptic so it is the ecliptic this is the ecliptic and extreme I think this is sun you can see now you have got this sun and this is the moon now it is not the full moon because on full moon sun and moon will be 180 degree apart and now it is not the full moon day date and date if you change to January 18 to say let us see if we let you go to February 18 where we are you can do little bit trial and error you can find out so you can see now sun is here but it is not winter solstice day but I think now it is actually a new moon time so I think this I did it somewhere but I think I do not remember the dates exactly you can bring sun and the winter solstice extreme end of this it will be somewhere here somewhere here and moon's longitude will be right ascension will be 12 hours different and also you will find that full moon the moon will be against the nakshatra moga so that has been done and it is regular I think so this is easy to find out by using little bit of trial and error that 2400 BC on such and such date full moon took place in moga it was the winter solstice day but Mahabharata war took place or the when Richard died it was not the full moon day it was winter solstice but seven days before the full moon so what happens the so now what will be this day therefore now to this whole thing represents 365 days but it takes how much time for it to come 25 2800 years so 7 days will mean how many years 7 into 7 by 365 into 25 26000 so this is about few 3 400 years so 24 BC and you reduce 5 or 600 years whatever comes you can calculate so that is the approximate time when this could have happened that on the suklasthami of the month when the full moon took place on the moga nakshatra and it was the winter solstice day so there are all these conditions have to be of course it is very clear with this it is difficult to do because moga nakshatra is not one point moga nakshatra spans how much 30 degrees so therefore there will be always a chance plus minus this way that way I personally believe so many people try to show that such and such rate such and such time that needs far more analysis but one thing is true you can say that Mahabharata work was approximately 15 to I think around 18 19 or 1500 kind of BC kind of things I think it will be around 1900 BC the reason is another because everything must match you know I think Balaram is described to have taken a path along the bank of Saraswati and went up to the place where it vanished in the desert Vinashana so there and in the geological research shows that Saraswati completely dried around 1900 BC so after few hundred years of that perhaps it will not be there most probably therefore around that time it happened but there is another clue that clue is as I mentioned that there is only one character who is found both in Puran and also in history that is Mahapardhananda so Vishnu Puran says that after Pariksit there are thousand fifty or thousand five hundred years when Nanda became the king Jagat Pariksitavu Janma Jagat Nanda Vishyachana Etadbharsha Sahasrantu Panchadasuttaram Gyan somebody says it is Panchasattuttaram somebody says Panchadasuttaram so whatever it is you will find you can easily calculate 1500 years was the time from Pariksit to Mahapardhananda Mahapardhananda ten generations from Chandraguddha's time so if you take twenty years or twenty five years per generation so another two hundred years so one thousand five hundred to two hundred years or one thousand fifty to two hundred years so twelve hundred fifty years and Chandraguddha was about two hundred fifty BC so you get about sixteen seventeen hundred BC on the other calculation which is nothing to do with astronomy so therefore it is opined by the experts like Bankini Chattapadhyay who did lot of research in 19th century on this that Mahapardha war took place around sixteen seventeen eighteen nineteen hundred years around that time you can tell approximately but not three thousand BC what many people say that because Kali Juga is described as three thousand one hundred two and that was considered to be the end of Mahapardha when the Kali started so many people do it that way and I think that is the source of mistake because Kali era was taken that day who told you did and we found that yes approximately the planets were taken and people described this as Kali era and Kali is the beginning of after Mahapardha war so people associate Mahapardha war is three thousand one hundred BC but calculations show other way now again another thing you see Puranic text Satapadha Brahmano says very clearly a very interesting thing the rising of Krittika now Krittika was a very important nakshatra bitwas it was the deity of the thing fire as I mentioned and it is mentioned that Krittika always rises in the east what does it mean something can rise in the east means it must be on the celestial equator but the nakshatra's are not on the celestial equator they are on the ecliptic so only way it can be also in celestial equator that when it is in one of the equinoctial point either vernal equinoctial point or the autumn now if you assume that it was an autumn equinoctial point you will find that it is very difficult it will be some few tens of thousands of years back which is not acceptable if it is on vernal equinoctial point you can easily see just now that Krittika is at the vernal equinoctial point around 2900 BC and you can see when it rises now it must rise then say if I give the date as 2400 most popular I think I will change it to 2900 let us see now let us see whether it rises Krittika in the east vernal equinox means vernal equinox means that when the ecliptic is coming from the south and intersects the here you can see this is Krittika this is Krittika it is very much near the intersection of this is the vernal equinoctial point but now if you say if you want to do where it will be now you see it is rising far north it is here it is rising here so again and again it is described that Krittika is rising exact in the east means it will be a description at least 2700, 2800 years BC that is another reference we get another thing we will get so all the Puranic texts this is the way the chronology has been derived by the foundation of scholars say Atharvabhadra says that vernal equinox at Rohini, Nakshatra so again the same way we will find that when Rohini Nakshatra is near the vernal equinox when it could be there this is more or less reasonable it is easy to identify the vernal equinoctial point and which Nakshatra is there so they find it is 3000 to 3500 BC it was the vernal equinoctial reference and Rig Vedic reference it gives quite a few references one is very interesting which is called Mozhu Vidya now Mozhu was the name of Mozhu Vidya and Mozhu Vidya is comparatively more recent term and the the sages used to tell that when people should be prepared for harvesting in this northern Punjab region West Punjab region and that is why it was called Mozhu Vidya and normally the harvesting etc all those things are the season basant starts now everybody cannot find out when is the winter solstice etc so the easy way to see that heliacal rising of some constellations so Triangulam which is they call Asini and the heliacal rising of Asini was found to be happening after 2 months of winter solstice that means on the onset of now you see here it says many slokas are there in Rig Veda where it says that may the 3 wheel car of the Ashins which is the harbinger of spring drawn by swift horses 3 cannot be filled with pleasure and every way auspicious come to our presence and bring prosperity to our people and all these things another many slokas are there in most cases now people have found that it is the heliacal rising of Triangulam so and you find that you find Triangulam to rise heliacally around 4000 days after 2 months of winter solstice another reference which I showed you before that finding the true south direction by joining alpha canis minoris with alpha canis majoris that also previous day I showed I think first lecture was that it was 4000 BC approximately are 4100 BC these 2 were in the same meridian that means if you join them it will point towards south pole so all these things another thing which in that means the Orion's head was near the vernal equinoctial point now it is quite far off but if you see at 4000 BC so date and time let me give 4000 BC so I think you will find vernal equinox is somewhere here so we have to go back computer will help us to rotate change the rotation of earth so you see this is the east that means this is the east and this is the vernal equinox should stop this is the vernal equinox this is the celestial equator and so this is vernal equinoctial point and this is the Orion and head of Orion is here okay and it cannot be on vernal equinox obviously because it is not on the ecliptic nor on celestial equator so it will never be on but its head will be nearest to vernal equinoctial point and that is what you find that the head of the Orion is near the vernal nearest to vernal equinox the vernal equinox is here and this is the head of the Orion so you see currently if you see that at present vernal equinox is where this is the vernal equinox point this is the vernal equinox point you can see so it is far away this is the Orion this is Orion this is Orion said and vernal equinox is somewhere so many indications you have to match just one description you cannot take and predict or take a decision there are many ways you have to do and you will find most of the things that way will ultimately lead to this kind of things I have already given to you that the vernal equinox was at Orion said or Mrigashira summer solstice what written in text was in Uttar Phalgni Bitar Leonis autumn equinox was in Mula that is lambda scorpionics and inter solstice location in Pudva Bhattrapada and all these descriptions match 4000 BC then Atri's description of that annular eclipse on the summer solstice day what has been analysed by Prof. P. Sengupta was 4100 BC that depended on the calculation of the partial eclipse of annular eclipse and as you are saying these calculations may not be very reliable and especially he did it a long time ago now we have computers so what I think you know you may not why I am saying this the same could have happened exact spot you may not be able to see that is the point for Panipra your Kurukshetra is a very spot but if you increase your size of the region then of course you can vary because you will find it there that is how people think that such a thing happened exactly where you saw that that you may not be able to see but annular eclipse happened time period etc. I have given my first slide already so I need not go into that and also as there is no need for to show the heliacal rising because we are short of time so this way Veda also refers to the fact that joining the stars alpha canis minor is alpha canis major is I told that is 4,350 BC now another very interesting astrology can be of our help exaltation of mass now due to the ellipticity of the earth and masses orbit the minimum distance from the earth is 55.35 into 10 raise to 6 kilometer between mass and earth and the maximum distance is 100.23 10 raise to 6 at the nearest position mass is 3 times brighter than the series compared to the situation when it is at the faintest with only 60% of the brightness of the series so with 6 times the brightness values of mass and this is called exaltation of mass in astrology in the post Vedanga Jyothi the exaltation of mass is said to have occurred at a position which is now away from the that current location by 13.7 degrees now where the exaltation takes place nowadays and that time when where it took place the difference is 13.7 degrees now since this shift is at the rate of now every century the location of the exaltation point of mass shifts by 0.4335 degree and the period because that is the rate of advance of perihelion of mass just now I told the mass orbits perihelion shift and exaltation will be always at the perihelion position so the rate at which perihelion position shift that is the way the location of the exaltation position of mass in the ecliptic will also shift the same way so per every century this position of exaltation shift by 0.4335 degrees so when it occurred at a location which is now at a distance of 13.7 degrees and that must have taken place almost 1160 B.C. so that is a post Vedanga period you know and exaltation of mass takes a mass repeats at intervals of 15 and 17 years alternatively but the perihelion position shifts that is what I mentioned so this is the picture that this is the star against which the perihelion of the mass is there and there is an exaltation so what happened this slowly shifts you know so exaltation position also will shift continuously maybe sometime you will find the exaltation of mass against star B when the line of upsides rotates to this position and you can easily find out the duration this angle divided by 0.4355 so that will give you so many centuries and obviously you can easily calculate so this calculation was again done very meticulously by Professor Rana of Ayuka because he is not lying he was a very outstanding astronomer in one 225 years it moves to one degree also the same thing 0.4 something else now another last topic I will talk about originality of ancient Indian astronomer now this was a matter of bitter controversy you know and they used to fight this is far worse than the emails our faculty members in the IIT Kanpur exchanges you know so I think European scholars they came in contact with the ancient Indian text they never knew about language like Sanskrit and they are so amazed to see its richness that's why they are very jealous to say that those things were done by them now as the level of excellence of the ancient Indian literature philosophy and science became gradually known it gave rise to severe controversies and I mentioned that they thought that these people could not have done that they are all bogus third-rate niggers and really society was extremely degenerate in 18th, 17th century and some of course were somewhat more scholarly they didn't have this kind of buyer they say no no no antiquity etc. so two things are one most important thing is the originality of the nakshatra system that was one of the major debating point because in Chinese they shoot with 24 stars there is a system they thought that that is the first nakshatra system in Arabic there is something like Manazil that also used to describe the locations of the moon and gave rise to the suspicion that the origin was in China or West Asia or Babylon because the any source of wisdom they generally has the tendency to take it to Babylon you know many of their scholars said that what is this anything good you find in either they said it must have happened in Babylon and it has come here now bio for example his opinion was that China was the origin based upon his personal impression and feelings the China these that and not based on any scientific reading rather in the book you will find I have given the detailed analysis from various sources now Sanskrit ultimately I will not go into those details but Max Muller did some linguistic analysis and he proved that nakshatra is fine mentioned in Indian text dating back to 3rd millennia BC of course this date was not by him this date was by the text we refers now the dating of those texts are that is 3rd millennia BC he also showed that the names of the three winter months in Chinese literature Pihua Mokua and Folkuna are derived from the Sanskrit name Pusha, Magha and Faluna and these names are linked with the typical Indian system of naming months where full moon takes place against nakshatra this system is not there in any other literature any other astronomy so he said that since China the names of the three winter months are according to the names of the Indian nakshatra which is followed there he said that it must have originated in India first and then going to China it could not have happened the other way and there are some other reasons of course there I don't have time to discuss everything another thing of course is very surprising that India was unknown to Chinese till 126 BC the name of river Sindhu appeared in Chinese literature in 65 BC later scholars like Thaibau proved that the nakshatra system could not have a Semitic origin either that means not in West Asia he showed from a study of the clay tablets found in Babylon that Babylonians were using the to indicate the positions of the planets and moon with respect to the 12 divisions of the ecliptic which we call signs they did not have the names but that was their system they never had 27 so they did not use the 27 nakshatas for that some scholars feel that since moon's 27 positions is not very difficult to observe many civilizations could have perhaps arrived at the same conclusion so there is nothing strange about it it was a very obvious thing to do so there is no need to fight like that another important point is the similarity with siddhantic astronomy and Greek astronomy the old it has been found I will not go into the detail description that is in the book you will find but the older version of Shurya siddhanta which was later changed by Varahamira it describes two distinct planetary theories in the older theory the planets are considered to be attached to invisible cords of air which drove the planets the cords of air through which the gods stationed at the apogee produced the motions were called probaham it is a very unique thing in Indian astronomy it is not there in Greek astronomy and this ancient system was also devised to explain the uneven motions of the planets why sometimes fast sometimes it is slow and the motions of the planets were classified into 8 classes far more sophisticated than Greek astronomy and it was before the Greeks came it was in the older version of Shurya siddhanta and the 8 classes of motions of the planets were vakra, anubhakra, kutila manda, mandalara samo, otishigra and sikha so qualitatively since they didn't have numbers to measure what they did they described it qualitatively with 8 different classes of motion which is obviously quite sophisticated period and this classification is considered to be the relic of some still forgotten parts of ancient Indian astronomy 12 science were also recognized as I mentioned even during the Mahabharata period but the names were not given now extensive analysis of the Indian and Greek system of European scholars revealed that the two systems are very different and the siddhantic astronomers used oval shaped epicycles and not circuits and the reason you know in Ptolemic system you could not match it well with one epicycle with circular shape then they added another epi-epicycle then another epi-epi-epicycle whereas Indian system they didn't use a circle at all they used an oval shaped body and what Burgess stated in the middle of 19th century yes sir so if it is tyco-bright then oval is elliptical orbit elliptic oval is like ellipse actually they didn't know the ellipse they called all such things as oval shaped even Kepler initially tried when that 8 minutes of arc he was unable to match the masses or be able he first tried it oval much later he came to ellipse to see the perfection he did lot of experiment with oval shaped like eggs you know the reason is that it is very psychological you see if sun is helping or influencing and sun is one side then the body cannot be symmetric like this tendency will be to consider sun centric or one focus so it tends to become an oval psychologically so Burgess stated and here I must think the Hindus original in regard to most of the elementary facts and principles of astronomy so most part also in their calculation of science and that the Greeks borrowed from them rather their facts and principles Burgess gave a detail in his arguments regarding the originality of the Indian astronomy in regard to the 27 asterisms and 12 science also he further mentions as regards the resemblance between the Greek and Hindu methods of calculating the true places of planets I think that only hints could have passed from one people to another we find it difficult to see precisely what it was that the Hindus borrowed since in no case do the numerical data and results in the two systems exactly correspond values are very different so it was definitely not a kind of copy maybe some ideas were exchanged and the Hindus are more nearly correct than the Greeks in their numerical values and of course there are many more points on this matter but without going further I will end this session by the following statement from play fair his paper in the transactions of Royal Society of Edinburgh about two centuries I quote of such high antiquity therefore must we suppose the origin of this astronomy unless we can believe that all the coincidences which have been enumerated are but the effects of chance or what indeed were still more wonderful that some ages ago there had arisen a neutron among the Brahmins to discover that universal principle which connects not only the most distant regions of space but the most remote periods of duration and they will grant to trace through the immensity of both in most subtle and complicated operations so I think friends I think I will stop here and I think that you will enjoy going through more elaborate text but the simpler version for a common man's language we have done at the request of the Ramakrishna Mission Institute of Culture which students can read of course what I have given more details are there more importantly this gives all the necessary bibliography and references if you want to read further all the references you will find here and that I have given this the book here as the primary reference but you can see the bibliography and of course this is the end of the lecture series and many thanks I never expected that there will be so many till the last lecture because normally I am told that it is the camera wall or camera man or the we have to take it somebody was telling that he was happy the lecturer that he was still here no sir I cannot leave that there is a carpet is mine I have to take it so many interesting stories you know the one person came to give a lecture and he is a very famous talk audience is there he was invited how long can I talk then the organizer the person like Amit said I think you are such an outstanding speaker coming from a distance you are so fortunate that you are here so you can speak as long as you want but we live in 55 minutes ok thank you friends thank you very much thank you to your power as a teacher you can still attract people so I will request everyone to stay back for a couple of minutes before he takes the questions and answers I will request professor Mahendra Varma to give a small memento on behalf of physics you are creating photo session photo session photo session thank you very much excellent ok now open for questions if you have any question and from Monday you can send request PPD files whoever ok so if you have any question so many which I visited recently there is supposed to be a pole what is today there is a pole if you see then the line will go to the south pole ok I am not sure which which area does it correspond to I have never visited ok listen you have given the pain drive they want to take because they need this ok ok there are no more questions you have a question please yes various what to be ok ok ok ok ok ok ok ok ok ok ok ok calendar committee calendar committee ok what is this what is yours this one I have to give my 15 minutes interview to Tushar, are you here? Yeah, yeah, he asked me everything, where I graduated from, whether my PhD in mechanical engineering and he said that he want to become a scientist, he said that's very good, excellent, but only unfortunate thing that he wants to do MBA, yeah. Nowadays, actually you know about 2000 years back, some of our rituals we started and that time it was the 14th of January was the date of winter solstice, that's why you are still doing that Makarsankanthi kind of thing, but which it is, it has nothing to do with that now, it has shifted to 21st December, but only about 2000 years back you can easily calculate considering the precision of the equipment, how many thousand years back it was the winter solstice and then we started our rituals and such things, you know. So it remains as 14th of January, but it has come, I think it is 15th because of the 76 years, yeah, so it is very easy to calculate that. Actually about approximately Vikram Saka was around 2000 years old, so you will find that it was started then and so it has shifted, but that has not been taken note of, we are taking the same date as the winter solstice, otherwise there is no significance of 14th of January. So no more questions, we will thank Professor Ghosh again, and also the team of Physics Society, Department of the Hard Work, Dipan Jain is with me, members from Lecture Hall and here I think all of you attended, so big hand for you.