Francis Watkins (1723 -1791) brass reflecting telescope with a 23 1/2” primary tube, 4 1/2" eyepiece extension tube, and 9" sighting tube with crosshairs; sliding screw rod focusing apparatus attaches to a polished speculum secondary mirror; adjusts with brass vertical adjustment gear wheel and thumbscrews; raised on an octagonal baluster column supported by three folding legs. Inscribed "Fra. Watkins Charing Cross London." Overall 28" length, 21 1/2" height (measured while horizontal). Historical Note: Francis Watkins' telescopes are associated with 18th c. British explorer James Cook, who in 1769 took an 18" Watkins telescope on his voyage to the Pacific to make astronomical observations including the Transit of Venus from Tahiti. Watkins apprenticed as an optician, eventually opening his own business in 1747 in London at 5 Charing Cross. Under the sign "Isaac Newton's Head" he produced various instruments with ground glass lenses. According to a 1763 advertisement, these included "Reading Glasses, [a] Great Variety of single, double and Solar Microscopes, Reflecting and Refracting Telescopes, of all Lengths and Sizes; Opera Glasses, Concave and Convex Mirrors of all Sizes, Book and Box Cameras of all Dimensions, all Sorts of Barometers and Thermometers, also Hydrometers, Hydrostatic Balances, air Pumps, and all other Optical and Philosophical Instruments." 

Excellent overall condition, functions smoothly; small 1/4" indentation to bottom of main tube; rear primary mirror dirty with disuse obscuring clear viewing.