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格里果里望远镜[Gregorian Telescope] [2005-9-25]
iamet 发表在 ¤〖天文〗
| A type of telescope developed by Scottish astronomer-mathematician James Gregory (1638-1675). Gregory described his design in his 1663 publication Optica Promota (The Advance of Optics). The Gregorian design consists of a concave secondary mirror, located outside the prime focus and angled to reflect the light back through a hole in the primary mirror (as is also done in a Cassegrain telescope). Both designs have the advantage over the Newtonian telescope in that they require shorter tubes for the same focal length.
The novelty of Gregory's design was to use both mirrors and lenses in his telescope. However, the first attempt to build a Gregorian telescope failed, and it wasn't until ten years later (spurred by the interest of Robert Hooke) that a working Gregorian telescope was actually constructed.
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