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Date: |
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Description: | T. Harris & Son / London / Night Glass
This non-achromatic telescope has a mahogany barrel and a single brass draw tube. The brass fittings include a sliding eyepiece cover (slightly damaged) and an objective lens cap. Unusually for a telescope of this date, there is no mechanical stop to prevent the draw tube from pulling out of the barrel.
An inscription on the draw tube names the maker as ?T. Harris & Son / London? and identifies the telescope as a 'Night Glass'. This means that it was designed for use at night and in poor light conditions.
It has a large objective lens to allow as much light as possible to enter the telescope. The telescope doesn?t have extra lenses to correct the inversion of the image, since the more lenses a telescope has, the greater the loss of light. The production of inverted images is typical of night telescopes.
Focal length; 28.5". O.G.diameter; 2.8".
Objective lens broken.
caption: Night telescope
caption: Night telescope - inscription | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Subjects: | astronomical telescopes Night telescope | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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