Astronomical adventures in India

2020 June 3

Jeremy Shears

Little did I know when I was writing about my 76mm airline-portable refractor (see the 2020 February Journal, p.37) that I would soon be relying on it rather heavily. I have recently been on a three-month work assignment in Bangalore, India. Not wanting to be deprived of optical aid for that long, I knew I already had the solution.

Observations from Bangalore

Bangalore is located 13° north of the equator and I was keen to make use of the location to explore more southerly skies. These were already quite familiar to me, as I lived in Singapore for several years which is more or less on the equator; I have also been to Australia and New Zealand on observing excursions. I was therefore looking forward to getting reacquainted. Unfortunately, Bangalore (population about 14 million) and Singapore have another factor in common: they are both heavily light-polluted.

Bangalore in the winter months experiences temperatures up to 30°C in the middle of the day, dropping to 18°C at dawn. The pleasant climate is helped by its 920m of altitude. However, temperatures start to increase during March, as does the dust haze due to the dryness.

I was staying on the eleventh floor of an apartment block, with a south-westerly facing balcony, and from there I did most of my observing. Orion transits almost overhead, with Sirius just below and Canopus further south of that. Most evenings I observed Venus, following its shrinking phase, but I could never spot any details. Observations of nebulae were challenging due to the light pollution of course, but star clusters – especially in Puppis – were excellent.

Escaping the light pollution

Although I was able to get out of Bangalore city to the 1,500m-high hill stations of the Nandi Hills, two hours north, the best skies I encountered were on a trip to south Goa during February.

Goa is on the west coast of India, overlooking the Arabian Sea. Watching the sunset was awe-inspiring as Venus became visible in the darkening sky, followed by Mercury which, fortuitously, was near maximum elongation. Many of the locals on the beach did not know what these two objects were and were amazed when they found out. An hour or two after sunset, there was a faint elongated glow in the west. This was not light pollution as there was no land for the next 3,000km. It was, of course, the zodiacal light; only the second time I have seen this phenomenon.

Again, the 76mm travel telescope came in handy, but perhaps the most enjoyable views were with a pair of 2.1×42 Vixen binoculars. These have a very wide field of view, allowing whole constellations to be observed, but they also boost the limiting magnitude by about 1.5 magnitudes compared to the naked-eye view. Perfect for scanning the Milky Way down through Carina.

Bangalore Planetarium

Established in 1989, the Jawaharlal Nehru Planetarium in central Bangalore is one of the five planetaria in India named after the country’s first prime minister. The Bangalore Planetarium is administered by the Bangalore Association for Science Education, which is tasked with popularising scientific subjects among the public, especially children. It has a Zeiss projector.

The planetarium complex also has an observatory dome housing a 150mm Zeiss refactor on a Coudé mount, equipped for visual, CCD and spectroscopic observation. Its location right in the city centre means that it is really only suitable for observing brighter objects – and of course the Moon is stunning through it, much to the delights of the visiting public.

The Indian Institute of Astrophysics (IIA) & a BAA connection

Bangalore hosts the headquarters of the IIA, the country’s main research institute for astronomy and astrophysics. The IIA has its origins in the Kodaikanal Solar Observatory, some 450km south of Bangalore. This observatory, which is still active and is part of the IIA, was established in 1899. One of its early directors was John Evershed (1864–1956), who was the first to observe radial motions in sunspots, a phenomenon now known as the Evershed effect.

John, a founder member of the BAA, worked at Kodaikanal with his wife, Mary Acworth Evershed (née Orr; 1867–1949). Mary was an accomplished astronomer in her own right, as well as a Dante scholar. She was also the first Director of the BAA Historical Section, from 1930 to 1944. Mary and John met on the 1896 BAA expedition to a total solar eclipse in Norway. Unfortunately, I never got the chance to visit Kodaikanal as it is rather difficult to access, involving a nine-hour car trip over challenging roads. Another time, perhaps!

However, I did have the honour of making contact with Prof G. C. Anupama, who is Dean of the IIA and Professor-in-charge of the Indian Astronomical Observatory. This observatory hosts several instruments, including the 2m optical–infrared Himalayan Chandra Telescope, located at 4,500m altitude near the border with China and Tibet. The telescope is operated remotely from Bangalore.

Prof Anupama is currently President of the Astronomical Society of India (ASI), the first woman to head this association of professional astronomers since it was formed in 1972. We took the opportunity of exchanging greetings between the BAA and the ASI.

Prof Anupama’s research interests include supernovae and cataclysmic variables, such as novae and dwarf novae. In fact, we both have our names (along with over 70 other joint authors) on two papers regarding the 2016 eruption of the recurrent nova in M31 known as M31N 2008-12a. Small world! I have suggested that if she sees any projects that the BAA Variable Star Section might become involved with, then we would be keen to assist.

Jantar Mantar, New Delhi

During a business trip to New Delhi, I visited the Jantar Mantar Observatory. Between 1727 and 1734 Maharaja Jai Singh II of Jaipur built five astronomical observatories in west-central India, all known by the name Jantar Mantar, which means ‘calculation instrument’. The primary purpose of the observatory was to compile astronomical tables and to predict the movements of the Sun, Moon and planets.

The Delhi Jantar Mantar has four main architectural structures built of stone and marble. The largest of these is the Samrat Yantra, or ‘Supreme Instrument’, which is a sundial with a gnomon some 39m along the hypotenuse. The Misra Yantra (or ‘Mixed Instrument’) was used to determine the shortest and longest days of the year and to calculate the exact moment of noon in various Indian cities. Meanwhile, a circular structure looking something like a miniature Colosseum, known as the Rama Yantra, was used to measure the altitude of stars.

Jantar Mantar’s sighting devices were designed for use with the naked eye, even though Jai Singh did possess a number of telescopes; the first recorded use of a telescope in India was in 1618.

(Images by Jeremy Shears.)