The item is a 6 inch transit circle. The transit circle is an instrument used to determine the declination of stellar onjects. It consists of a circular scale kept perpendicular to the rotating axis of a telescope tube.

The fond contains Results of observations of the fixed stars made with the Meridian Circle at the Government Observatory , Madras

Results of observations of the fixed stars made with the Meridian circle at the Government Observatory, Madras in the years 1880,1881 and 1882.

Results of observations of the fixed stars made with the Meridian circle at the Government Observatory, Madras in the years 1877, 1878 and 1879.

Results of observations of the fixed stars made with the meridian circle at the Government Observatory, Madras in the years 1865, 1866 and 1867.

Results of observations of the fixed stars made with the meridian circle at the Government observatory Madras in the years 1874, 1875 and 1876.

Results of observations of the fixed stars made with the Meridian Circle at the Government Observatory, Madras, in the years 1871, 1872 and 1873.

Results of observations of the fixed stars made with the Meridian Circle at the Government Observatory , Madras, in the year 1862, 1863 and 1864 under the Direction of Norman Robert Pogson

Results of observatios of the fixed stars made with the Madras meridian circle, Vol. IX - General Catalogue.Fixed stars

This item was an instrument used for measuring the intensity of a light source. It uses a light-sensing device that is calibrated to express intensity in a standard unit. Some optical elements such as lens etc. are also employed to incerase the sensitivity of the instrument.