Showing 83 results

Archival description
Transit Circle - 6 inch
IND-IIA-F045 · Fond · 1850

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.

Madras Observatory
IND-IIA-F041 · Fond · 1850

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.

Airy, George Biddell
Stereoscope
IND-IIA-F047 · Fond · 1986

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.

Madras Observatory
IND-IIA-F306 · Fond · 1909-1918

The album contains archival documents related to John Evershed, a brief biography, photographs, scientific discoveries in astrophysics, drawings, and sketches of observations from the Kodaikanal Solar Physics Observatory. The album starts with a crisp description of the life of John Eveshed. The photographs in the album are based on the following themes: the mechanical workshop and the spectroheliograph, the plaque installed in 1975 in Kodaikanal to commemorate the discovery of the Evershed effect, observatory buildings, and Evershed with the Kodaikanal Observatory staff. In addition, a detailed description related to the Evershed effect is reproduced from bulletin No. XV(1909) of Kodaikanal Observatory, a photo of Halley's comet and a picture of the moon hand-drawn by Evershed, spectra of nova aquilae in 1918, pencil sketches by Evershed on the solar prominences are preserved in this album. Each item is provided with captions.

Indian Institute of Astrophysics
IND-IIA-F305 · Fond · 1909-1953

The album contains photographs related to the professional and personal life of John Evershed, particularly in India, Australia, and England, from 1909 to 1953. The album shows different events such as John Evershed using a spectroheliograph at Kodaikanal, camp life in India, Evershed with his wife at Kashmir, a group photo including Evershed, Thomas Royds, and the Kodaikanal Observatory staff, the visit of Evershed for his research at Srinagar, Kashmir, and Wallal, a photo of Evershed and his signature. At the album's end, the photo of his old age at Highbroom and Heath cottage with his pet dog- Brock, has also been archived.

Indian Institute of Astrophysics