![William Herschel's reflecting telescope of 40 ft (12 m) focal length, 1789 (1807). Artist: Unknown Stock Photo - Alamy William Herschel's reflecting telescope of 40 ft (12 m) focal length, 1789 (1807). Artist: Unknown Stock Photo - Alamy](https://c8.alamy.com/comp/AJA4RF/william-herschels-reflecting-telescope-of-40-ft-12-m-focal-length-AJA4RF.jpg)
William Herschel's reflecting telescope of 40 ft (12 m) focal length, 1789 (1807). Artist: Unknown Stock Photo - Alamy
![Sir William Herschel's Great Forty Foot telescope. Sir William Herschel's telescope or the Great..., Stock Photo, Picture And Rights Managed Image. Pic. MEV-10934710 | agefotostock Sir William Herschel's Great Forty Foot telescope. Sir William Herschel's telescope or the Great..., Stock Photo, Picture And Rights Managed Image. Pic. MEV-10934710 | agefotostock](https://previews.agefotostock.com/previewimage/medibigoff/4887fc467388661d73b8a18c01b08b1d/mev-10934710.jpg)
Sir William Herschel's Great Forty Foot telescope. Sir William Herschel's telescope or the Great..., Stock Photo, Picture And Rights Managed Image. Pic. MEV-10934710 | agefotostock
![William Herschel's 40 foot telescope, also known as the Great Forty Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 47 William Herschel's 40 foot telescope, also known as the Great Forty Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 47](https://c8.alamy.com/comp/T964MB/william-herschels-40-foot-telescope-also-known-as-the-great-forty-foot-telescope-was-a-reflecting-telescope-constructed-between-1785-and-1789-at-observatory-house-in-slough-england-it-used-a-47-inch-diameter-primary-mirror-with-a-1200-cm-focal-length-it-was-the-largest-telescope-in-the-world-for-50-years-it-may-have-been-used-to-discover-enceladus-and-mimas-the-6th-and-7th-moons-of-saturn-it-was-dismantled-in-1840-today-the-original-mirror-and-a-10-foot-section-of-the-tube-remain-T964MB.jpg)
William Herschel's 40 foot telescope, also known as the Great Forty Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 47
![a William and Caroline Herschel's 40-foot telescope in Slough, England,... | Download Scientific Diagram a William and Caroline Herschel's 40-foot telescope in Slough, England,... | Download Scientific Diagram](https://www.researchgate.net/publication/334758949/figure/fig1/AS:786192975028225@1564454420939/a-William-and-Caroline-Herschels-40-foot-telescope-in-Slough-England-1789-1-b-Two_Q320.jpg)
a William and Caroline Herschel's 40-foot telescope in Slough, England,... | Download Scientific Diagram
![Herschel's Great Telescope, artwork. Also known as Herschel's 40-foot telescope, it was designed by William Herschel (1738-1822), one of the foremost Stock Photo - Alamy Herschel's Great Telescope, artwork. Also known as Herschel's 40-foot telescope, it was designed by William Herschel (1738-1822), one of the foremost Stock Photo - Alamy](https://c8.alamy.com/comp/2ADM1WT/herschels-great-telescope-artwork-also-known-as-herschels-40-foot-telescope-it-was-designed-by-william-herschel-1738-1822-one-of-the-foremost-2ADM1WT.jpg)
Herschel's Great Telescope, artwork. Also known as Herschel's 40-foot telescope, it was designed by William Herschel (1738-1822), one of the foremost Stock Photo - Alamy
![The Forty-Foot Telescope at Slough. Photographed by Sir John F.W. Herschel photographed 9 September 1839; this print made in August 1890 | Sir John Frederick William HERSCHEL The Forty-Foot Telescope at Slough. Photographed by Sir John F.W. Herschel photographed 9 September 1839; this print made in August 1890 | Sir John Frederick William HERSCHEL](https://www.jonathanahill.com/pictures/6384.jpg?v=1541600749)