Indian Astronomy in the 18th and 19th Centuries
Stone Observatories of Jai Singh
Sawai Jai Singh (1686-1743) constructed five observatories in India at
Delhi, Jaipur, Benaras, Ujjain, and Mathura. The one in Mathura no longer
exists. The observatories in Benaras and Ujjain are in a state of
disrepair. In these observatories Jai Singh installed astronomical
instruments of pre-telescopic era. Some of the instruments were made
out of metal but most were constructed of masonry. Many of the
instruments were Jai Singh's own invention such as Jai Prakasa Yantra,
Rama Yantra, and Samrat Yantra. Jai Singh was aware of the existence
of telescopes but the ones that come into his hands were poor in quality,
suffering from defects like spherical and chromatic aberrations. He opted
for instruments made out of stone and masonry. Jai Singh produced a set
of astronomical tables completed sometime between 1727 and 1735. The
tables were called Zij-i Muhammad Shahi - the astronomical
tables of Muhammad Shah, the reigning monarch at that time.
Madras Observatory
The old Madras Observatory was established by the East India Company
in 1792. The guiding force behind the construction of this observatory
was Michael Topping a sailor-astronomer. He acquired several astronomical
instruments, some from William Petrie a noted English astronomer. Among
the instruments that he had were achromatic refractors, astronomical
clocks with compound pendulum, and an excellent transit instrument. The
observing program included stars, the Moon, and eclipses of Jupiter's
satellites. For more than a century measurements of stellar positions
and brightnesses were made. During this period several Government
astronomers headed the observatory. Notable among them were Goldingham,
Taylor, Jacob, and Pogson. The last astronomer was well known for the
Pogson's scale in photometric work. At the end of the nineteenth century the
Kodaikanal observatory was constructed which subsumed the role of the
Madras observatory. From then onwards the Madras observatory had a
side role in weather forecasting and time service.
Calcutta Observatory
A small observatory was established in Calcutta by the East India
Company around 1825 to serve the Survey Department. It had a transit
telescope, alti-azimuth circle and later an astronomical telescope
was added. Some astronomical observations were performed of lunar
transits and eclipses of Jupiter's satellites, but mostly it was
confined to routine time recording and meterological observations.
Royal Observatory at Lucknow
King Nasiruddin Haydar, who reigned in Oudh, established an observatory
in Lucknow during 1832. According to some reports it was one of the
best equipped observatories in India at that time. It had a mural
circle, a transit telescope, an equatorial telescope, and astronomical
clocks. Maj. Richard Wilcox was in charge of the observing program.
Wilcox and his assistants observed the major planets, the larger
asteroids like Ceres and Vesta, eclipses of Jupiter's satellites,
occultations of stars by the Moon, and meridonial transit of stars.
After Wilcox's death the observatory was closed due to political
reasons and was destroyed during the Indian War of Independence in
1857.
Travancore Observatory
In 1836, the Raja of Travancore had an observatory built in Trivandrum.
He appointed John Caldecott as its director. For the observatory,
Caldecott acquired a transit instrument, two mural circles, an
equatorial telescope, and magnetic and meteorological instruments. He
collected an enormous amount of astronomical data, which included the
observations and computations of the orbital elements of the comets of
1843 and 1845. After Caldecott's death the next notable director was
John Broun. But Broun's interest was mainly in meteorology and
terrestrial magnetism. Broun is associated with the discovery of the
relationship between solar activity and subsequent changes in terrestrial
magnetism. After Broun's departure in 1865 the observatory was closed
by the then Raja of Travancore.
Takhta Singhji Observatory
Owing to the efforts of a Parsi physicist, K. D. Naegamvala, an observatory
was established in Pune around 1882 through a grant from the Maharaja of
Bhavnagar. The observatory had a 20-inch Grubb reflector for both visual
and photographic work, spectroscopes, and sidereal clocks. It was a premier
spectroscopic observatory in India. Naegamvala made spectroscopic
observations of the solar chromosphere and corona during the solar
eclipse of 1898. He also made spectroscopic studies of the Orion nebula
and sunspot groups. After Naegamvala's retirement in 1912 the observatory
was dismantled and the instruments were transferred to the fledgling
observatory in Kodaikanal.
Miscellaneous Observatories
In 1875, Father Lafont established a spectroscopic laboratory in St.
Xavier's College, Calcutta in order to carry out solar and stellar
spectroscopic work. The observatory had equatorial telescopes, transit
instruments, and spectroscopes. Observations of solar prominences were
carried out regularly. Later the focus of the observatory was shifted to
meteorological work. Currently, the observatory is being used only
for teaching purposes.
Mention must also be made of the observatory in Presidency College,
Calcutta. It was constructed in 1900 through a grant from the Maharaja
of Tipperah who donated a 4.5-inch Grubb reflector. In 1922 it
received as a gift from the Astronomical Society of India an 8-inch
telescope.
Indian Astronomy in the early 20th Century
Kodaikanal Observatory
After the Madras famine of 1886-87, an inquiry commission appointed
by the Government recommended that the relation between sunspot
activity and the distribution of rains be studied. The site for
a solar observatory was selected in Kodaikanal and the observatory
started functioning from 1900. Observations of sunspots, solar
prominences, and solar photography were carried out on a regular
basis from the following year. Spectroscopic instruments were
acquired to obtain the spectra of sunspots and spectro-heliographs
of the sun in the lines of ionized calcium and hydrogen. The
Kodaikanal and Madras Observatory had the same director. Over
the years the role of the Madras Observatory was confined to the
measurement of time, but the observations of the sun still continue
at the Kodaikanal Observatory.
John Evershed became the director of the Kodaikanal Observatory in
1911. He started a program of photographing solar prominences and
sunspot spectra. He noticed that many of the Fraunhofer lines
in the sunspot spectra were shifted to the red. He showed that
these shifts were Doppler. This discovery came to be known as the
Evershed effect. From the nature of the sunspot spectra Evershed
concluded that they were similar to stars of spectral type K.
Another discovery of Evershed bears mentioning. While comparing
the spectra of the limb of the sun with that obtained from the
center of the disk he noticed a shift towards the red at the
limb. He first attributed that to motion but when Einstein's
gravitational displacement was considered to be a factor, Evershed
recomputed his results. His conclusion was that while Einstein's
gravitational displacement could account for most of the shift,
there still remained a definite unexplained residual shift.
Nizamiah Observatory
A wealthy nobleman in Hyderabad acquired a 15-inch Grubb refractor
and established an observatory at Begumpet, Hyderabad. The
observatory was taken over by the Nizam's Government in 1908 and it
soon became involved in an international program of mapping the sky.
In this carte-du-ciel program 18 observatories with similar
instruments took part. For this program an 8-inch astrograph was
acquired. The observatory was alloted the zone between declinations
-17° to -23°. Later it also covered the zone between declinations
+39° to +36°, originally given to Potsdam. The observations were
carried out under 3 directors - Chatwood, Pocock, and Bhaskaran.
Twelve catalogues containing 800,000 stars were published.
T. P. Bhaskaran also started an observing program of variable stars
with the 15-inch Grubb telescope. It was during his time that control
of the observatory passed from the Nizam's Government to Osmania
University. Akbar Ali succedeed Bhaskaran in 1944. Ali started a
program of double star measurement. He felt the need to introduce
the new study of photoelectric photometry and placed an order for
a 48-inch telescope for the observatory.
Astronomy in the Universities
In the first half of the twentieth century most of the observational
work was being conducted at Kodiakanal and Nizamiah Observatories.
Much of the theoretical work was being done at three centers -
Calcutta University, Allahabad University, and Benaras Hindu University.
At Calcutta University, Prof. C. V. Raman attracted a bright group of
young physicists. Among them was M. N. Saha. Saha's greatest contribution
was in the theory of thermal ionization and its application to stellar
atmospheres. Saha moved to Allahabad University and started a strong
group on theoretical astrophysics. Several members of this group made
important contributions in the field of stellar interiors. Another
group inspired by V. V. Narlikar worked on cosmology at the Benaras
Hindu University. His son J. V. Narlikar carried on this line of
research.
Post Independence Optical Astronomy in India
The main centers for optical astronomy in India are Indian Institute
of Astrophysics at Bangalore, Center for Advanced Study in Astronomy
at Osmania University, Uttar Pradesh State Observatory at Naini Tal,
and Physical Research Laboratory at Ahmedabad.
Indian Institute of Astrophysics, Bangalore
In 1971 the old Madras and Kodaikanal Observatory were made into
a single autonomous research institution. The solar observations
continued to be performed at Kodaikanal. New instruments had been
added over the years - a large solar telescope with a high dispersion
spectrograph, a coronagraph, and a monochromatic heliograph. The solar
telescope now has a photoelectric magnetograph to make fine measurements
of magnetic and velocity fields in the sun. This observatory has sent
out several expeditions to observe solar eclipses.
Optical observations of stars and galaxies are conducted from Kavalur
in Tamil Nadu. The 20-inch Grubb reflector that was acquired from
the Maharaja Takhtasingji Observatory was tranferred from Kodaikanal
to Kavalur. After Bappu became the director a 30-inch reflector was
added to the observatory for photoelectric photometry. During Bappu's
directorship a 2.3 meter telescope was designed and fabricated
indigeneously. This telescope is used at prime (f/3.25) and
cassegrain (f/13) focii for imaging and medium resolution spectroscopy
using CCD detectors. There is also a 1-meter Carl Zeiss telescope
used for CCD imaging and low resolution spectroscopy.
Center for Advanced Study in Astronomy, Osmania University
The Nizamiah Observatory, which had 15-inch refractor and a 8-inch
astrograph, was under the administration of Osmania University.
In 1959 a separate teaching department was started. In 1964 the
University Grants Commission recognized the department and its
observing facilities as a Centre for Advanced Study in Astronomy.
A 48-inch telescope was commissioned in 1968 and installed
near the villages of Japal and Rangapur. The center under the
directorship of K. D. Abhyankar had an active program in
photoelectric photometry and spectroscopic observations of
variable stars.
Uttar Pradesh State Observatory, Naini Tal
The government of Uttar Pradesh established an observatory in 1954
at Benaras. It was later shifted to Naini Tal when Vainu Bappu
was its Chief Astronomer. Sinvhal, who succeded Bappu, acquired
a 1-meter Zeiss telescope. The observatory also has a 15 inch and a
20-inch reflector with folded Cassegrain and Coude foci for solar work.
The observing program includes photoelectric photometry of variable
stars, comets, and occultation work. In 1977, during the occultation
of SAO158687 by Uranus, observers at Naini Tal detected the ring
system around this planet.
Physical Research Laboratory, Ahmedabad
There is a 48-inch telescope at Gurushikhar on Mt. Abu. The telescope
is operated by the Physical Research Laboratory and is used mainly
for infrared work. They have a 256 x 256 pixel HgCd array detector
for 2 micron imaging. The observing program includes spectroscopy and
polarimetry. PRL also has a solar observatory in Udaipur. It has a
12-ft solar telescope on a small island in the midst of Fateh Sagar
Lake. The observatory is involved in high resolution chromospheric
and photospheric studies of flares.
Radio Astronomy in India
Tata Institute of Fundamental Research (TIFR), Bombay
TIFR operates the radio telescope at Ooty. The telescope is 530 meters
long and 30 meters wide. It is a cylindrical paraboloid placed on
a mountain slope aligned with the earth's rotation axis. The telescope
is operated at 326.5 MHz. Positions and structures of thousands of
radio sources with arcsecond resolution have been determined, which
have helped studies in observational cosmology. New pulsars have
been discovered. And the electron densities in various parts of our
Galaxy have been measured using interplanetary scintillations
of radio sources.
Raman Research Institute, Bangalore
The Raman Research Institute and the Indian Institute of Astrophysics
jointly operate a large low frequency (~35 MHz) array at Gauribidnur.
The telescope is being used for studies of the Sun, Jupiter, HII regions,
our Galaxy, and external galaxies.
Physical Research Laboratory, Ahmedabad
PRL operates a network of three stations - Thaltej, Rajkot, and Surat.
Regular interplanetary scintillation observations are made.
Giant Meter Wave Radio Telescope (GMRT), Pune
A VLA like Y-synthesis telescope with 45 meter dishes is under
construction near Pune. The frequency range will be from 150 MHz to
1 GHz. The observations will be mainly of extragalactic sources.
The telescope will also search for primordial hydrogen from highly
red-shifted 21-cm lines.
Reference
Sen, S.N. and Shukla, K.S., (1985), History of Astronomy in India,
Publisher: Indian National Science Academy, New Delhi.
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