This item was a stellar object requires two coordinates to locate it on the sky, as the sky is a two-dimensional plane. One of these coordinates known as declination. This is similar to the two co-ordinates viz. latitude and longitude, defining a point on the surface of the earth. 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.

This fond contains materials related to John Evershed that contains general local office materials including letters of all local government and administrations, proceedings, reports to the government of India etc., A large portion of the collection series contains information on observations from various scientists.

The letter is from Gilbert T. Walker to Charles Michie Smith discussing about the enlargement of photos, the orientation of spectroheliograph, scientific instruments, and the sending of 'sun pictures' plates to Christie.

The letter was written by E. C. J. Bond who was the officer in-charge No. 18 party (Magnetic), Survey of India to the Director of the Madras and Kodaiknal Observatories, Kodaikanal. In this letter, he claims to have sent a registered parcel post to Kodaikanal that contained three strips of fine phosphor bronze fibre and four incredibly fine tungsten wires that could be used to suspend the magnetograph's declination. The letter was written in Dehra Dun in 1919.

Letter from E. C. J. Bond to the Director of Kodaikanal Observatory about recording the magnetic observations

The letter was a request for sending copies of all printed forms, instructions, and full particulars of the photographic process in connection with the 8-inch solar photographs done by the Superintendent of Trigonometrical Survey.

The letter was written by E. C. J. Bond, the officer in charge No. 18 party (Magnetic), Survey of India, to the Director of the Solar Physics Observatory, Kodaikanal. E. C. J. Bond has mentioned some suggestions to the magnetic observers to get accurate values during the observations. It was written in 1920 in Dehra Dun.