Agasthyarkoodam’s lost observatory

Subject: Science and technology

Section: Space technology

Concept:

Agasthyarkoodam on the Western Ghats once (in Nineteenth-century) housed an observatory that was established by Scottish meteorologist John Allan Broun.
Broun used it to record magnetic and meteorological observations in tandem with the Thiruvananthapuram astronomical observatory.
Broun’s astronomical research in India began after he was invited by the ruler of the erstwhile Travancore Uthram Tirunal Marthanda Varma to helm the Thiruvananthapuram (then Trevandrum) observatory following the death of its first director John Caldecott in 1849.
As terrestrial magnetism research requires simultaneous measurements from two different locations, he established his second observatory at Agasthyar mountain at a height of 6,200 ft above sea level.
The observatory started recording observations in July 1855. However, it was closed in 1881 by the then Madras Governor Sir William Denison.
Notably, Broun was awarded the Keith Medal from the Royal Society of Edinburgh and the Royal Medal from the Royal Society of London.

Magnetic observatory

Magnetic observatories continuously measure and record Earth’s magnetic field at a number of locations.
In an observatory of this sort, magnetized needles with reflecting mirrors are suspended by quartz fibres.
Light beams reflected from the mirrors are imaged on a photographic negative mounted on a rotating drum. Variations in the field cause corresponding deflections on the negative.
A print of the developed negative is called a
Their magnetograms are photographed on microfilm and submitted to world data centres, where they are available for scientific or practical use.

Applications :

Applications of magnetic observatories include the creation of world magnetic maps for navigation and surveying; correction of data obtained in air, land, and sea surveys for mineral and oil deposits; and scientific studies of the interaction of the Sun with Earth, etc.