18th Century Non Achromatic Decagonal Reverse Taper Telescope By John Gilbert

The use of more than three lenses was adopted around 1753 by a lot of the leading London makers as a way in which to improve the field of view without increasing chromatic aberration. During the eighteenth and early nineteenth centuries, the Gilbert family of Tower Hill carried a huge reputation, rivalling that of the Dollond and Ramsden for their skill of manufacture.

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