The graphic telescope is an optical aid for artists. It was patented in 1811, and is a device which enables artists to view magnified images and trace them onto paper.


The Whipple Museum has a graphic telescope (Images 1 & 2) made by its inventor, Cornelius Varley, XR around 1840. The optical principles involved are related to those used in other artistic aids such as the camera obscura and the camera lucida.
An advertisement for the instrument begins with the following claim:
By this instrument, any person, who can make a good outline, may draw, correctly, all kinds of objects, the most distant, as well as near, magnified to any scale.
And continues:
Buildings, Carts, Wagons, Agricultural Implements, &c. Boats and Shipping when ashore, with all the minutiae or rigging and curves of the vessel, may be traced in true proportion and perspective, let them be ever so complicated; more particularly, views of Towns, things which few persons would have the patience to attempt, without such an instrument. (1)
Looking into the eyepiece of the graphic telescope, the user sees a clear image on a speculum mirror and a less clear image superimposed over the paper below. Tracing this image, the artist could then accurately draw their subject matter.
Boris Jardine
Boris Jardine, 'The graphic telescope and Varley's artwork', Explore Whipple Collections, Whipple Museum of the History of Science, University of Cambridge, 2008 [http://www.hps.cam.ac.uk/whipple/explore/astronomy/artandastronomy/graphictelescope/, accessed 21 May 2012]