The item comprises observations made as Madras Equatorial Observations of Comet Encke; its observations were taken in August 1878 by N.R. Pogson. Encke's Comet (official designation: 2P/Encke) is a periodic comet that completes an orbit of the Sun once every 3.3 years.

The item contains observation notes of the comet Tempel on 21 and 22 August 1862. Tempel 1 is a Jupiter-family comet.

The item comprises observations made as Madras Equatorial Observations of Comet Biela; its observations were taken in December 1872 by N.R. Pogson. Comet Biela (official designation: 3D/Biela) was a periodic Jupiter-family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela.