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Newtonian secondary mirror
An elliptical plane mirror made as a secondary mirror for a Newtonian reflector telescope. The diameter of the minor axis for this mirror is 1.97 inches (50.04mm). Mounted on wooden block, the mirror is cut at right angles to its surface.
In a Newtonian reflector telescope the eyepiece is at the side of the tube. Light comes in at one end, is reflected off the objective (or primary) mirror and onto this mirror which directs the light towards the eyepiece. 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.
In a Newtonian reflector telescope the eyepiece is at the side of the tube. Light comes in at one end, is reflected off the objective (or primary) mirror and onto this mirror which directs the light towards the eyepiece. 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.
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Object Details
| ID: | AST0812 |
|---|---|
| Collection: | Astronomical and navigational instruments |
| Type: | Newtonian secondary mirror |
| Display location: | Not on display |
| Creator: | Herschel, William |
| Date made: | circa 1800 |
| People: | Johann Alexander Herschel |
| Credit: | National Maritime Museum, Greenwich, London, Herschel Collection |
| Measurements: | Overall: 50.038 mm |