Colaba Observatory

History

The Colaba Observatory was built in 1826 by the East India Company to aid shipping in Bombay’s port through astronomical observations and time-keeping. The 165-year-old building later served as office space for the Indian Institute of Geomagnetism. In 1841, Arthur Bedford Orlebar, then Professor of Astronomy at Elphinstone College in Bombay, began recording geomagnetic and meteorological data there. Magnetic measurements were taken irregularly from 1841 to 1845, then every two hours, and eventually every hour. Francis Ronalds, Honorary Director of the Kew Observatory, supplied advanced equipment to Colaba in the following years. In 1846, the East India Company ordered his full apparatus for collecting and measuring atmospheric electricity. Later superintendents Charles Montriou and Edward Francis Fergusson stayed in touch with Ronalds and trained with him at Kew. In 1867, Kew’s photo-recording machines were sent to Colaba, allowing automatic, continuous readings of atmospheric pressure, temperature, and geomagnetic intensity. Charles Chambers, later a Fellow of the Royal Society, was Director when these machines arrived; his analysis of the geomagnetic measurements and their underlying physics brought the observatory greater recognition. After his death in February 1896, Nanabhoy Ardeshir Framji Moos became the first Indian Director. Holding an engineering degree from Poona and a higher science degree from Edinburgh, Moos ensured efficient operations, regular data analysis, and the launch of seismological observations. In 1900, Bombay’s plan to electrify its horse-drawn trams threatened to corrupt the magnetic data with electromagnetic interference.