Ramesh Kapoor

Indian Institute of Astrophysics | IIAP

This paper presents observations of Comet 1P/Halley made from India during its apparition in 1910. The comet was well observed from various locations, and newly formed observatories made observations throughout the visibility phase. We also discuss the impact of the apparition on people from different walks of life.

In this paper we outline the efforts made by the East India Company, the British colonial authorities, visiting astronomical expeditions and expatriate amateur astronomers to establish astronomical observatories in India during the three centuries prior to Indian Independence in 1947. The focus of this paper is therefore primarily on the emergence...

This paper is about sightings and astronomical observations of the 1874 transit of Venus made from the Indian region. The sources of the information presented here range from some classic texts and historiographies, publications and records of institutions, and chronicles, to accounts by individuals. Of particular interest is the fact that the tran...

Meteor phenomena are always fascinating and capture popular attention. This paper reports results of a search for references to and records of meteor showers observed in the Indian region, until the close of the nineteenth century. The sources explored were the Indian classics and chronicles, institutional reports and accounts by individuals, inclu...

There is reference to a total solar eclipse over Kurukshetra in an ancient Indian text, the Srimadbhagvata (also the Bhagavata). The occasion drew not just Lord Krsṇa, his brother Balarama and their clan from Dwarka, but also their parents and the folk from the Braj region, the Pandava family and all the prominent characters of the epic Mahabharata...

This paper discusses the observations of the Great March Comet of 1843 made from India. The observers were at various locations and the newly formed observatories participated in the astronomical observations spread over a long phase of the apparition. Of great interest were the observations by Dr George Buist at the Colaba Observatory made on 5 an...

The Tai-Ahom are an ethnic group, the admixed descendants of the Tai or Shan people who migrated from North Burma into the Brahmaputra Valley of Assam in India in the early decades of the thirteenth century. Their history is meticulously documented in chronicles called buranjis, manuscripts written in the Ahom or Assamese language. The Ahom Buranji...

On 02 June 1858 at the Observatory of Florence, Giambattista Donati (1826–1873) discovered a faint nebulous patch what was destined to become one of the most brilliant comets in history. Named after him, Donati’s Comet (1858 VI; C/1858 L1 (Donati)) enthralled sky watchers in Europe and elsewhere like never before. This paper brings together tales o...

This paper brings together India-centric accounts of the Great Comet that appeared in 1882. It grew to be the most magnificent one seen since the Great Comet of 1843, and was observed from throughout the Indian Subcontinent. The comet of 1882 has been variously designated as the Great September Comet, 1882 II, 1882b and C/1882 R1. We look into the...

In a recent issue of the Journal of Astronomical History and Heritage I looked into two seventeenth century Persian paintings depicting tailed objects (comets or possibly fireballs) in the sky (Kapoor, 2019). One of these, the painting by Muhammad Zaman, has a date inscribed at the lower left as ‘sana 7’. Elsewhere, the date has been interpreted as...

This contribution presents earliest records in the Indian stone inscriptions and literature that specifically mention the eclipse as total or annular and the eclipses that timed with wars. Solar cult temples can be found all over India. In a few, the assigned dates coincide or are close to the dates of solar eclipses of large magnitude in the area.

A solar eclipse with a totality of rather long duration took place on 02 July 2019. The path of totality started east of New Zealand in the southern Pacific Ocean and passed over parts of Chile and Argentina. I visited La Serena in Chile with an intent to watch and photograph The Great South American Eclipse. This article is a record of my wonderfu...

In the Theodore M. Davis Collection of the Metropolitan Museum of Art in New York there are two seventeenth century Persian paintings by Muhammad Zaman and Ali Quli Jubbahdar that depict comets or fireballs. From the inscriptions on them, the paintings were dated and on that basis the comets identified as those seen in the years CE 1664/1665 and CE...

Captain John Warren, the Acting Astronomer at Madras Observatory between 1805 and 1811, observed the Great Comet of 1807 (now C/1807 R1) and computed its orbit. He wrote up his observations in a paper titled ―An account of the comet, which appeared in the months of September, October and November 1807 and sent this to England, but it was not publis...

Captain John Warren was the Acting Astronomer of Madras Observatory during the years 1805‒1811 when the Astronomer John Goldingham went to England on leave. At Madras, Warren observed the Great Comet of 1807 (C/1807 R1), computed its orbit, and prepared a manuscript that he sent to London in 1809 (which was not published). Subsequently, Warren obse...

For astronomical observations, a telescopic device was used in India, within a decade of its invention. The year was 1618 but what astronomical objects were observed? That is connected with the tale of two great comets of November 1618.

The revolt against the British broke out at Meerut on 10 May 1857 that soon turned into a Great Uprising and shook the foundations of the colonial power in India. A conjunction of Mars and Saturn took place in July 1857. A solar eclipse occurred on 18 September 1857, two days before the capture of Delhi by the British. There followed a lunar eclips...

Two celestial occurrences find place in the incidents related to the great poet-saint Guru Nanak (1469-1539 CE), the founder of Sikhism, or in his teachings. The first one referred to as lamma tara (long star) figures in a hymn in the Sri Guru Granth Sahib and the other a solar eclipse that occasioned while Guru Nanak was visiting Kurukshetra. I co...

The year 1618 in astronomy was a unique one in that it presented three bright cometary apparitions in quick succession. The comets created enough sensation and belong to the era when Galileo‘s telescopic observations had created a paradigm shift in our perception of the heavens and Johannes Kepler was introducing a fundamental change in mathematica...

In this study, I look into the writings of Ghulām Husain Jaunpūrī (1790–1862), a well-known mathematician and communicator of modern astronomy in Persian in the early 19th century, probably the first Indian traditional astronomer on record to systematically make modern astronomical observations, namely those of a bright comet in 1825 with a sextan...

Abū'l Faẓl, the celebrated Prime Minister of the Mughal Emperor Akbar, recorded in the Akbarnāmā (a highly-acclaimed biographical account of the Emperor) the appearance of a comet during the 22 nd year of Akhar‗s reign, in 985 A.H. From the recorded date, it turns out that Abū'l Faẓl was an independent discoverer of one of the most famous comets in...

Srimadbhagvad Gita which is taken to be part of the great epic Mahabharata, composed through 400 BCE to 400 CE, was a later addition to it, in the early centuries after Christ. The Mahabhārata is about a great war that took place between the Kauravas and the Pandavas at Kurukshetra at the junction of the Dvapara and Kali eras. When was that? That i...

Unexpected phenomena like eclipses, comets, meteors and earthquakes were regarded ill omens for rulers and emperors and so were routinely monitored by historians and chroniclers. Recording such events in the political history was a well-established tradition in the ‘Middle East’ empires, even by Muslim historians in India. I look into the record of...

In this note, I look into the record of a comet in the writings of an 18th century Indian historian Sayyid Muh ammad 'Alī al-H usaini, that he says appeared in 1154 AH (1741–42). No astronomical detail of the observation is given. The circumstances suggest him to be an independent discoverer of the bright comet of 1742, now designated C/1742 C1....

This paper is about sightings and astronomical observations of the 1874 transit of Venus made from the Indian region. The sources of the information presented here range from some classic texts and historiographies, publications and records of institutions, and chronicles, to accounts by individuals. Of particular interest is the fact that the tran...

This paper, the first of two, is about sightings and astronomical observations of transits of Venus across the disk of the Sun made from the Indian region. The period covered in this first paper is from ancient times up to and including the 1769 transit. The sources of the information presented here range from some classical texts and historiograph...

The Persian polymath Abū ʿAlī Ibn Sīnā (980 – 1037 CE), known to early Western sources as Avicenna, records in one of his works, Compendium of the Almagest that ‘I say that I saw Venus as a spot on the surface of the sun’. The date and place of the observation are not given. This statement has been quoted subsequently by some Muslim astronomers, fo...

T. P. Bhaskaran, director of the Nizamiah Observatory during 1918-44, used to write astronomical notes for the “Science Notes and News” section of Current Science. We re-visit his ‘Astronomical Notes’ that featured the bright comet of 1941 in the February and March 1941 issues of the journal.

This note celebrates the discovery of the Comet Bappu–Bok–Newkirk 1949 IV, the only one with an Indian’s name to it. Then a research student at Harvard, M. K. Vainu Bappu (1927–82) was destined to set modern astronomy in newly independent India on an ambitious path to progress.

This note celebrates the discovery of the Comet 1949 IV Bappu-Bok-Newkirk, the only comet with an Indian’s name to it. Then a research student at Harvard, M. K. Vainu Bappu (1927-82) was destined to set modern astronomy in newly independent India on an ambitious path to progress.

This note celebrates the discovery of the Comet Bappu-Bok-Newkirk 1949 IV, the only one with an Indian's name to it. Then a research student at Harvard, M. K. Vainu Bappu (1927-82) was destined to set modern astronomy in newly independent India on an ambitious path to progress.

The Persian polymath Abu Ali ibn Sina (980--1037 CE), known to early Western sources as Avicenna, records that ``I say that I saw Venus as a spot on the surface of the sun''. This statement has been quoted, for example, by Nasir al Din al Tusi (1201--1274 CE). A Transit of Venus indeed took place during ibn Sina's life time, that is on 24 May 1032...

In this paper we present excerpts from the records at the Indian Institute of Astrophysics Archives that show that T.G. Taylor, an astronomer at the Madras Observatory, was an independent discoverer of the Great Comet of 1831 (C/1831 Al) on 7.00972 January 1831 UT, although John Herapath who first observed the comet from Hounslow Heath (England) on...

The article gives a very brief history of the astronomical observatories built by the king Sawai Jai Singh II in the 18th Century.

The article discusses telescopic discoveries of asteroids from India.

The real physicochemical nature of the classical metal preparations - the bhasmas in the Indian Systems of Medicine (ISM) is not very clear. Of late, doubts have been raised as to their utility and suitability as medicine. We take a closer look at these aspects. We find that the bhasmas are in fact products of classical alchemy - inorganic compound...

In this communication we present the circumstances of the total solar eclipse of Oct 17, 1762 that passed over India, specific to Amritsar to recreate the ambience that may serve as a definitive input to certain perceptions that the total eclipse affected a fierce battle on the day between Ahmed Shah Abdali’s forces and the Sikhs at Amritsar, forci...

As a prelude to the forthcoming total solar eclipse of July 2009, this article recounts tales of a few total solar eclipses that had been observed from India by the teams of the Indian Institute of Astrophysics, Bengaluru. Apart from the total eclipses of 1980 and 1995, it briefly tells about the historical eclipse of 1762, and, the expeditions of...

We have investigated in detail the geometry of the open magnetic field line structure of an oblique dipole rotator, with a view to attaining a better understanding of the geometry of pulsar beams in the polar cap model of pulsar emission. We find that the open field lines divide into two branches, both of which are required to describe the full pol...

We present here an independent method to understand emission altitudes in radio pulsars showing triple profiles. The centres of core and conal components in triple profiles are often non coincident in longitude. Treating these effects as a generic property we seek an explanation by attributing different emission altitudes to these components. The e...

We present a new method for investigating emission altitudes of radio pulsar core and conal components by attributing them different altitudes and by providing a framework to understand the resulting longitude offsets between them which are frequently observed. By investigating the contributions to these offsets due to aberration and the magnetic f...

Pulsar radio pulses are made up of the so called core and conal components. A remarkably precise relation for core component widths, found observationally, in effect specifies the size of the polar cap on pulsars. Inclusion of general relativistic effects makes the theoretical size dependent on the pulsar mass. The observed core width relation thus...

A remarkably precise observational relation for pulse core component widths of radio pulsars is used to derive stringent limits on pulsar radii, strongly indicating that pulsars are strange stars rather than neutron stars. This is achieved by inclusion of general relativistic effects due to the pulsar mass on the size of the emission region needed...

An estimate of the effect of light bending and redshift on pulsar beam characteristics has been made using a weak Kerr metric for the case of a 1.4 M ⊙ neutron star with a radius in the range 6-10 km and rotation periods of 1.56 ms and 33 ms, respectively. Assuming that the pulsar emission has the form of a narrow conical beam directed away from th...

The effect of light bending and redshift on pulsar beam characteristics is estimated using the weak form of the Kerr metric applicable to a slow-rotating neutron star. The beam is found to diverge by a factor of 2 or less and to suffer an intensity reduction by an order of magnitude when emitted from close to the star's surface. This flattening of...

This article introduces fast pulsars to informed readers (article in Italian)

Results are presented of a study of frequency shifts in radiation from the surface of rapidly rotating neutron stars and rotation-induced spectral line broadening as a function of their mass. It is found that, despite large rotation rates, the gravitational effects dominate over the Doppler contribution to the frequency shifts over the allowed mass...

The article discusses nature of fast pulsars, with periods in the millisecond range.

Collimated beams (jets) with opening angles of order of a few degrees observed in extragalactic energetic sources are generally explained as having been produced by accreting supermassive black holes or supermassive magnetized rotators in centers of galaxies (For a review see Wiita 1985). Considering the first alternative, several workers have atte...

General relativistic effects due to spacetime curvature and rotation on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. It is found that for the millisecond pulsar PSR 1937+214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency m...

The astrophysical aspects of proposals of escape of supermassive blackholes from galactic nuclei and their implications in relation to quasars are discussed. We conclude that high velocity recoil of the central engine can at best be considered an exception rather than a rule since it requires a violent release of mass energy in an asymmetrical mann...

The author has used the impulsive approximation technique to numerically estimate the effect of dynamical friction on the motion of a supermassive black hole (mass ≅ 109M_sun;) through a galaxy (mass ≅ 1011M_sun;) which has recoiled from the center of the latter as a result of rocket effect (anisotropic emission of gravitational radiation or plasma...

The effect of defocusing introduced by spacetime curvature in a narrow conical beam of particles emanating from the vicinity of a compact mass is considered, with application to the study of jets. The deflection in particle trajectories brought about by the attraction of the central compact mass which widens the beam (the decollimation) is calculat...

General relativistic effects due to spacetime curvature and rotation on the arrival time of pulsar signals are investigated using rotationally perturbed spherical metric. We find that for the millisecond pulsar PSR 1937+214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency mapping)...

Central cores of compact radio sources are believed to contain supermassive black holes accreting material from their vicinity which produce fast moving plasma in the form of directed beams (jets), with apparent opening angles ≥5° (Rees et al. 1981). In case, the jets are produced and their collimation is established on scales few times the Schwarz...

A numerical study has been made of the motion of a compact object consisting of a supermassive black hole with a dense cluster of stars around through a galaxy which has recoiled from the center of the latter as a result of anisotropic emission of gravitational radiation or asymmetrical plasma emission. We find that the effect of dynamical friction...

The effects of spacetime curvature and rotation on the pulse profile of fast pulsars are studied using a rotationally perturbed spherical metric and a representative choice of the equation of state for neutron star matter. Spacetime curvature is found to produce a divergence in the pulse width and a deamplification of the pulse intensity. Rotation...

Propagation of photons in the space-time exterior of a rapidly rotating neutron star is investigated, using a rotationally perturbed spherical metric, to determine the pulse profile of fast pulsars. It is found that space-time curvature produces a substantial amount of divergence in the pulse beam width accompanied by a reduction in the pulse inten...

The recent discovery of millisecond pulsars1,2 has led to several theories about the structure3–8 and radiation characteristics9–11 of rapidly rotating neutron stars. The rapid rotation rate implies that such pulsars will be compact5 (implying large space-time curvature) and that surface emission characteristics will differ significantly from the n...

We have used the impulsive approximation technique to numerically estimate the effect of dynamical friction on the motion of a supermassive black hole (mass 109 M ) through a galaxy (mass=1011 M ) which has recoiled from the center of the latter as a result of anisotropic emission of gravitational radiation or asymmetric plasma emission. We find th...

The solar corona was photographed at an effective wavelength of 6300 Å during the total eclipse of 1983, June 11 at Indonesia. From the isophotes of the corona, the intensity distributions along the equator, poles, streamers and gaps have been derived. The brightness distribution and the Ludendorff parameters of this corona are typical of the inter...

General relativistic effects of rotation on the structure and surface emission of the fast pulsar PSR 1937+214 are illustrated using a rotationally perturbed interior spherical metric. The results are found to differ markedly from those derived on the basis of simple spherical models, and are expected to be generally valid for the class of fast pul...

The frequency shifts and line broadening of radiation from the surface of rapidly rotating neutron stars are calculated using a rotationally perturbed interior spherical metric and a representative choice of the equation of state for neutron star matter. The effect of rotation on the surface redshift and Doppler broadening are found to be substanti...

Shklovsky (1982) has hypothesized escape of accreting supermassive black holes from galactic nuclei as a consequence of asymmetric ejection of plasma clouds from their accretion disks and their subsequent defunction for explaining evolutionary effects in quasars. It has been argued here that such an interpretation must accomodate the possibility of...

It is argued that accreting supermassive black holes ejected from centers of galaxies are the likely models for the quasars observed in association with galaxies. Also pointed out are the implications of a recent suggestion by Horák (1982) to account for the excess redshifts of such quasars due to a combined effect of peculiar Doppler-motion and th...

An analytical study has been carried out of the non-tangential emission of photons in the orbital plane from a monochromatic source of radiation orbiting a black hole, using the method of geometrical optics. The formulation is applicable to eccentric orbits. The frequency shift in radiation, which is a combination of Doppler effect and gravitationa...

The article reminisces the happenings at the Total Solar Eclipse camp of the Indian Institute of Astrophysics at Jawalgera in Karnataka on the day of the eclipse, February 16, 1980.

A study has been made of the motion of a test particle in the background of a white hole particularly from the view point of its visibility to an observer at infinity. It is shown that radial as well as non-radial photons from such a particle can leak through the Schwarzschild radius even when the particle and the white hole boundary have not yet b...

It is shown that non-radial light rays emitted from the surface of a white hole can emerge from inside the Schwarzschild barrier. The upper limit on their impact parameter is calculated under the requirement that such rays are blueshifted. The apparent angular size of the white hole determined by blueshifted rays is shown to grow so rapidly in the...

This article introduces black holes to the lay reader.

The article introduces black holes to astronomers and informed readers.

Gravitational recoil of a gigantic black hole (M∼108–9 M⊙) formed in the nonspherical collapse of the nuclear part of a typical galaxy can take place with an appreciable speed as a consequence of the anisotropic emission of gravitational radiation. Accretion of gaseous matter during its flight through the galaxy results in the formation of a glowin...

It is shown that a photon emitted in the forward direction by a charged particle moving in an equatorial circular orbit centred on a highly collapsed mass M, the radius being slightly in excess of one and a half times the Schwarzschild radius, is strongly blueshifted when it arrives at a distant receiver. A ring shaped emitting region composed of s...

WE wish to point out an interesting effect associated with light emitted in the forward direction by a source circulating in an equatorial plane around a highly collapsed object or a black hole of mass M. The essential feature of the emission is that provided the radius a of the orbit in Schwarzschild's coordinates exceeds 3GM/c 2, the light emitte...

This work is about sightings and astronomical observations of transits of Venus across the disk of the Sun made from the Indian region. The sources of the information presented here range from some classic texts and historiographies, publications and records of institutions and chronicles to accounts by some individuals. Of particular interest is t...