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This fond contains correspondences related to clocks in Madras and Kodaikanal Observatory

This fond contains correspondences related to time signals

The fond contains observations of the meridian circle reductions ( refers to the process of correcting the observed zenith distances measured by a meridian circle instrument ) taken from the Madras Observatory from the year 1862 to 1887. Meridian circle reductions refers to a process in astronomy and celestial navigation that involves observations made with a meridian circle instrument.

The fond contains observations of the meridian circle reductions ( refers to the process of correcting the observed zenith distances measured by a meridian circle instrument ) taken from the Madras Observatory from the year 1862 to 1887. Meridian circle reductions refers to a process in astronomy and celestial navigation that involves observations made with a meridian circle instrument.

This item was a optical instrument named as Stereoscope. Stereoscopes are apparently those optical devices that help to view the two images separately and with relaxed eyes. There are two types of stereoscopes as: lens or pocket stereoscopes and mirror stereoscopes. Lens or pocket stereoscopes are great for viewing the whole overlap area of prints up to 9 cm × 13 cm or parts of larger patterns. On the other hand, mirror stereoscopes were designed to accept standard 23 cm × 23 cm metric air photos and work well with A4/US letter-sized prints. Most models come with magnifying options up to eight times, which is pretty impressive. One cool thing about mirror stereoscopes is that they are large enough to allow the analyst to draw beneath them, so it is possible to trace objects identified in the stereoview with a pen onto one of the images or a transparent overlay. However, it's important to remember that this sketch wouldn't have the geometric properties of a map as it contains all distortions present in the base image.

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.