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Description: | Unfinished 6-inch Newtonian primary mirror of speculum metal. When finished this mirror would probably be made to have a focal length of around 7ft. The actual diameter of this mirror is 165.1mm. One surface has been roughly smoothed, in preparation for grinding.
William Herschel, with help from his brother Alexander and his sister Caroline made a number of these mirrors to go in the telescopes they made to use and to sell. A mirror of this size and focal length would have been used in one of their 7ft telescopes.
AUDITED Negative Number C1115
caption: Gregorian primary mirror | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Subjects: | speculum metal mirrors A Catalogue of Instruments made and (or) used by Sir William Herschel as Preserved at Slough & examined ther in 1924 May & June A Peep into Herschel's Workshop Newtonian | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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