Sunday, 8 July 2012

Camera obscura

While in Grahamstown, I took some of my family to the Observatory Museum. Its Victorian camera obscura is the only one of its type in the southern hemisphere and one of only two in the world (the other being in Edinburgh).

A camera obscura is an optical device which predates the camera. The name originates in Latin and refers to a darkened room: camera means “vaulted chamber or room” and obscura means “dark”.

The museum was originally a nineteenth century jeweller’s shop and family home. The original owner and designer of this unusual building, Henry Carter Galpin, was a successful watchmaker and jeweller who constructed the camera obscura in 1882. He was interested in natural history, music, mechanics, astronomy and optics. The museum also includes a Meridian Room where Galpin could ascertain the precise time of local noon (14 minutes behind South African standard time) and a Telescope Room which contains the telescope which was originally installed in the rooftop observatory.

We climbed up a long and very narrow spiral staircase in the highest tower to reach the camera obscura. It works through a system of lenses and a mirror in a revolving turret in its roof and projects a panorama of the city onto a concave viewing surface in the darkened observation room beneath.

It’s fascinating and our guide was knowledgeable and friendly (though the building itself looks in need of maintenance).

This photograph of the image in the camera obscura is not as clear as the image itself. And had it been a sunnier day the image would have been even sharper.


Once locals would set their watches by the time on the clock tower but the clock is no longer working and these days each clock face seems to show a different time..!


You can find out more about the Observatory Museum at http://www.grahamstown.co.za and on Wikipedia.

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