Original mirror for William Herschel's forty-foot telescope, 1785.
- Object Number:
- 1932-567 Pt1
- type:
- components , concave mirrors and metal mirrors
Original mirror for William Herschel's forty-foot telescope, 1785.
- Made:
- 1785 in England, Slough and Maidenhead
- maker:
- William Herschel
The first 48-inch speculum mirror cast with metal cover by Sir William Herschel in 1785 for his 'Forty Foot' telescope at Slough, England.
The astronomer, Sir William Herschel made this 48-inch concave metal mirror for his '40-Foot Telescope' at Slough, England. Cast in 1785, the mirror is made of speculum, a bronze alloy with arsenic for a more lustrous finish. Weighing only half a ton, the mirror proved to be too thin to hold its shape properly once it had been ground and polished to its final form. A few years later, a heavier second mirror was cast which was used in preference to the original one. Completed in 1787, Herschel's great telescope soon became a wonder of the age. It quickly became a landmark of Slough visited by the rich and famous visiting the king at nearby Windsor.
Details
- Category:
- Astronomy
- Object Number:
- 1932-567
- Materials:
- complete, speculum (alloy of copper and tin) and iron
- Measurements:
-
overall (including ring): 150 x 1260 x 1260 mm
- credit:
- Revd Sir John Charles William Herschel
